diff --git a/composer.json b/composer.json
index e0544b61fb..46fdef1121 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "psr/link": "^1.0",
         "psr/log": "~1.0",
         "psr/simple-cache": "^1.0",
-        "symfony/contracts": "^1.0.2",
+        "symfony/contracts": "^1.1",
         "symfony/polyfill-ctype": "~1.8",
         "symfony/polyfill-intl-icu": "~1.0",
         "symfony/polyfill-intl-idn": "^1.10",
@@ -55,6 +55,7 @@
         "symfony/finder": "self.version",
         "symfony/form": "self.version",
         "symfony/framework-bundle": "self.version",
+        "symfony/http-client": "self.version",
         "symfony/http-foundation": "self.version",
         "symfony/http-kernel": "self.version",
         "symfony/inflector": "self.version",
@@ -101,8 +102,10 @@
         "doctrine/reflection": "~1.0",
         "doctrine/doctrine-bundle": "~1.4",
         "monolog/monolog": "~1.11",
+        "nyholm/psr7": "^1.0",
         "ocramius/proxy-manager": "~0.4|~1.0|~2.0",
         "predis/predis": "~1.1",
+        "psr/http-client": "^1.0",
         "egulias/email-validator": "~1.2,>=1.2.8|~2.0",
         "symfony/phpunit-bridge": "~3.4|~4.0",
         "symfony/security-acl": "~2.8|~3.0",
diff --git a/src/Symfony/Component/HttpClient/CHANGELOG.md b/src/Symfony/Component/HttpClient/CHANGELOG.md
new file mode 100644
index 0000000000..44594a71d0
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/CHANGELOG.md
@@ -0,0 +1,7 @@
+CHANGELOG
+=========
+
+4.3.0
+-----
+
+ * added the component
diff --git a/src/Symfony/Component/HttpClient/Chunk/DataChunk.php b/src/Symfony/Component/HttpClient/Chunk/DataChunk.php
new file mode 100644
index 0000000000..618112834d
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Chunk/DataChunk.php
@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Chunk;
+
+use Symfony\Contracts\HttpClient\ChunkInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+class DataChunk implements ChunkInterface
+{
+    private $offset;
+    private $content;
+
+    public function __construct(int $offset = 0, string $content = '')
+    {
+        $this->offset = $offset;
+        $this->content = $content;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isTimeout(): bool
+    {
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFirst(): bool
+    {
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isLast(): bool
+    {
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContent(): string
+    {
+        return $this->content;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getOffset(): int
+    {
+        return $this->offset;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getError(): ?string
+    {
+        return null;
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Chunk/ErrorChunk.php b/src/Symfony/Component/HttpClient/Chunk/ErrorChunk.php
new file mode 100644
index 0000000000..0c3f8dfc62
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Chunk/ErrorChunk.php
@@ -0,0 +1,106 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Chunk;
+
+use Symfony\Component\HttpClient\Exception\TransportException;
+use Symfony\Contracts\HttpClient\ChunkInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+class ErrorChunk implements ChunkInterface
+{
+    protected $didThrow;
+
+    private $offset;
+    private $errorMessage;
+    private $error;
+
+    /**
+     * @param bool &$didThrow Allows monitoring when the $error has been thrown or not
+     */
+    public function __construct(bool &$didThrow, int $offset, \Throwable $error = null)
+    {
+        $didThrow = false;
+        $this->didThrow = &$didThrow;
+        $this->offset = $offset;
+        $this->error = $error;
+        $this->errorMessage = null !== $error ? $error->getMessage() : 'Reading from the response stream reached the inactivity timeout.';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isTimeout(): bool
+    {
+        $this->didThrow = true;
+
+        if (null !== $this->error) {
+            throw new TransportException($this->errorMessage, 0, $this->error);
+        }
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFirst(): bool
+    {
+        $this->didThrow = true;
+        throw new TransportException($this->errorMessage, 0, $this->error);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isLast(): bool
+    {
+        $this->didThrow = true;
+        throw new TransportException($this->errorMessage, 0, $this->error);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContent(): string
+    {
+        $this->didThrow = true;
+        throw new TransportException($this->errorMessage, 0, $this->error);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getOffset(): int
+    {
+        return $this->offset;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getError(): ?string
+    {
+        return $this->errorMessage;
+    }
+
+    public function __destruct()
+    {
+        if (!$this->didThrow) {
+            $this->didThrow = true;
+            throw new TransportException($this->errorMessage, 0, $this->error);
+        }
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Chunk/FirstChunk.php b/src/Symfony/Component/HttpClient/Chunk/FirstChunk.php
new file mode 100644
index 0000000000..d891ca856d
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Chunk/FirstChunk.php
@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Chunk;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+class FirstChunk extends DataChunk
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function isFirst(): bool
+    {
+        return true;
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Chunk/LastChunk.php b/src/Symfony/Component/HttpClient/Chunk/LastChunk.php
new file mode 100644
index 0000000000..84095d3925
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Chunk/LastChunk.php
@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Chunk;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+class LastChunk extends DataChunk
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function isLast(): bool
+    {
+        return true;
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/CurlHttpClient.php b/src/Symfony/Component/HttpClient/CurlHttpClient.php
new file mode 100644
index 0000000000..08bbb46d08
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/CurlHttpClient.php
@@ -0,0 +1,374 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Symfony\Component\HttpClient\Exception\TransportException;
+use Symfony\Component\HttpClient\Response\CurlResponse;
+use Symfony\Component\HttpClient\Response\ResponseStream;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+use Symfony\Contracts\HttpClient\ResponseStreamInterface;
+
+/**
+ * A performant implementation of the HttpClientInterface contracts based on the curl extension.
+ *
+ * This provides fully concurrent HTTP requests, with transparent
+ * HTTP/2 push when a curl version that supports it is installed.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+final class CurlHttpClient implements HttpClientInterface
+{
+    use HttpClientTrait;
+
+    private $defaultOptions = self::OPTIONS_DEFAULTS;
+    private $multi;
+
+    /**
+     * @param array $defaultOptions     Default requests' options
+     * @param int   $maxHostConnections The maximum number of connections to a single host
+     *
+     * @see HttpClientInterface::OPTIONS_DEFAULTS for available options
+     */
+    public function __construct(array $defaultOptions = [], int $maxHostConnections = 6)
+    {
+        if ($defaultOptions) {
+            [, $this->defaultOptions] = self::prepareRequest(null, null, $defaultOptions, self::OPTIONS_DEFAULTS);
+        }
+
+        $mh = curl_multi_init();
+
+        // Don't enable HTTP/1.1 pipelining: it forces responses to be sent in order
+        if (\defined('CURLPIPE_MULTIPLEX')) {
+            curl_multi_setopt($mh, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
+        }
+        curl_multi_setopt($mh, CURLMOPT_MAX_HOST_CONNECTIONS, $maxHostConnections);
+
+        // Use an internal stdClass object to share state between the client and its responses
+        $this->multi = $multi = (object) [
+            'openHandles' => [],
+            'handlesActivity' => [],
+            'handle' => $mh,
+            'pushedResponses' => [],
+            'dnsCache' => [[], [], []],
+        ];
+
+        // Skip configuring HTTP/2 push when it's unsupported or buggy, see https://bugs.php.net/76675
+        if (\PHP_VERSION_ID < 70215 || \PHP_VERSION_ID === 70300 || \PHP_VERSION_ID === 70301) {
+            return;
+        }
+
+        // HTTP/2 push crashes before curl 7.61
+        if (!\defined('CURLMOPT_PUSHFUNCTION') || 0x073d00 > ($v = curl_version())['version_number'] || !(CURL_VERSION_HTTP2 & $v['features'])) {
+            return;
+        }
+
+        // Keep a dummy "onPush" reference to work around a refcount bug in PHP
+        curl_multi_setopt($mh, CURLMOPT_PUSHFUNCTION, $multi->onPush = static function ($parent, $pushed, array $rawHeaders) use ($multi) {
+            return self::handlePush($parent, $pushed, $rawHeaders, $multi);
+        });
+    }
+
+    /**
+     * @see HttpClientInterface::OPTIONS_DEFAULTS for available options
+     *
+     * {@inheritdoc}
+     */
+    public function request(string $method, string $url, array $options = []): ResponseInterface
+    {
+        [$url, $options] = self::prepareRequest($method, $url, $options, $this->defaultOptions);
+        $scheme = $url['scheme'];
+        $authority = $url['authority'];
+        $host = parse_url($authority, PHP_URL_HOST);
+        $url = implode('', $url);
+
+        if ([$pushedResponse, $pushedHeaders] = $this->multi->pushedResponses[$url] ?? null) {
+            unset($this->multi->pushedResponses[$url]);
+            // Accept pushed responses only if their headers related to authentication match the request
+            $expectedHeaders = [
+                $options['headers']['authorization'] ?? null,
+                $options['headers']['cookie'] ?? null,
+                $options['headers']['x-requested-with'] ?? null,
+                $options['headers']['range'] ?? null,
+            ];
+
+            if ('GET' === $method && !$options['body'] && $expectedHeaders === $pushedHeaders) {
+                // Reinitialize the pushed response with request's options
+                $pushedResponse->__construct($this->multi, $url, $options);
+
+                return $pushedResponse;
+            }
+        }
+
+        $curlopts = [
+            CURLOPT_URL => $url,
+            CURLOPT_USERAGENT => 'Symfony HttpClient/Curl',
+            CURLOPT_TCP_NODELAY => true,
+            CURLOPT_PROTOCOLS => CURLPROTO_HTTP | CURLPROTO_HTTPS,
+            CURLOPT_REDIR_PROTOCOLS => CURLPROTO_HTTP | CURLPROTO_HTTPS,
+            CURLOPT_FOLLOWLOCATION => true,
+            CURLOPT_MAXREDIRS => 0 < $options['max_redirects'] ? $options['max_redirects'] : 0,
+            CURLOPT_COOKIEFILE => '', // Keep track of cookies during redirects
+            CURLOPT_CONNECTTIMEOUT_MS => 1000 * $options['timeout'],
+            CURLOPT_PROXY => $options['proxy'],
+            CURLOPT_NOPROXY => $options['no_proxy'] ?? $_SERVER['no_proxy'] ?? $_SERVER['NO_PROXY'] ?? '',
+            CURLOPT_SSL_VERIFYPEER => $options['verify_peer'],
+            CURLOPT_SSL_VERIFYHOST => $options['verify_host'] ? 2 : 0,
+            CURLOPT_CAINFO => $options['cafile'],
+            CURLOPT_CAPATH => $options['capath'],
+            CURLOPT_SSL_CIPHER_LIST => $options['ciphers'],
+            CURLOPT_SSLCERT => $options['local_cert'],
+            CURLOPT_SSLKEY => $options['local_pk'],
+            CURLOPT_KEYPASSWD => $options['passphrase'],
+            CURLOPT_CERTINFO => $options['capture_peer_cert_chain'],
+        ];
+
+        if (!ZEND_THREAD_SAFE) {
+            $curlopts[CURLOPT_DNS_USE_GLOBAL_CACHE] = false;
+        }
+
+        if (\defined('CURLOPT_HEADEROPT')) {
+            $curlopts[CURLOPT_HEADEROPT] = CURLHEADER_SEPARATE;
+        }
+
+        // curl's resolve feature varies by host:port but ours varies by host only, let's handle this with our own DNS map
+        if (isset($this->multi->dnsCache[0][$host])) {
+            $options['resolve'] += [$host => $this->multi->dnsCache[0][$host]];
+        }
+
+        if ($options['resolve'] || $this->multi->dnsCache[2]) {
+            // First reset any old DNS cache entries then add the new ones
+            $resolve = $this->multi->dnsCache[2];
+            $this->multi->dnsCache[2] = [];
+            $port = parse_url($authority, PHP_URL_PORT) ?: ('http:' === $scheme ? 80 : 443);
+
+            if ($resolve && 0x072a00 > curl_version()['version_number']) {
+                // DNS cache removals require curl 7.42 or higher
+                // On lower versions, we have to create a new multi handle
+                curl_multi_close($this->multi->handle);
+                $this->multi->handle = (new self())->multi->handle;
+            }
+
+            foreach ($options['resolve'] as $host => $ip) {
+                $resolve[] = null === $ip ? "-$host:$port" : "$host:$port:$ip";
+                $this->multi->dnsCache[0][$host] = $ip;
+                $this->multi->dnsCache[1]["-$host:$port"] = "-$host:$port";
+            }
+
+            $curlopts[CURLOPT_RESOLVE] = $resolve;
+        }
+
+        if (1.0 === (float) $options['http_version']) {
+            $curlopts[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_0;
+        } elseif (1.1 === (float) $options['http_version'] || 'https:' !== $scheme) {
+            $curlopts[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_1;
+        } elseif (CURL_VERSION_HTTP2 & curl_version()['features']) {
+            $curlopts[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_2_0;
+        }
+
+        if ('POST' === $method) {
+            // Use CURLOPT_POST to have browser-like POST-to-GET redirects for 301, 302 and 303
+            $curlopts[CURLOPT_POST] = true;
+        } else {
+            $curlopts[CURLOPT_CUSTOMREQUEST] = $method;
+        }
+
+        if ('\\' !== \DIRECTORY_SEPARATOR && $options['timeout'] < 1) {
+            $curlopts[CURLOPT_NOSIGNAL] = true;
+        }
+
+        if (!isset($options['headers']['accept-encoding'])) {
+            $curlopts[CURLOPT_ENCODING] = ''; // Enable HTTP compression
+        }
+
+        foreach ($options['raw_headers'] as $header) {
+            if (':' === $header[-2] && \strlen($header) - 2 === strpos($header, ': ')) {
+                // curl requires a special syntax to send empty headers
+                $curlopts[CURLOPT_HTTPHEADER][] = substr_replace($header, ';', -2);
+            } else {
+                $curlopts[CURLOPT_HTTPHEADER][] = $header;
+            }
+        }
+
+        // Prevent curl from sending its default Accept and Expect headers
+        foreach (['accept', 'expect'] as $header) {
+            if (!isset($options['headers'][$header])) {
+                $curlopts[CURLOPT_HTTPHEADER][] = $header.':';
+            }
+        }
+
+        if (!\is_string($body = $options['body'])) {
+            if (\is_resource($body)) {
+                $curlopts[CURLOPT_INFILE] = $body;
+            } else {
+                $eof = false;
+                $buffer = '';
+                $curlopts[CURLOPT_READFUNCTION] = static function ($ch, $fd, $length) use ($body, &$buffer, &$eof) {
+                    return self::readRequestBody($length, $body, $buffer, $eof);
+                };
+            }
+
+            if (isset($options['headers']['content-length'][0])) {
+                $curlopts[CURLOPT_INFILESIZE] = $options['headers']['content-length'][0];
+            } elseif (!isset($options['headers']['transfer-encoding'])) {
+                $curlopts[CURLOPT_HTTPHEADER][] = 'Transfer-Encoding: chunked'; // Enable chunked request bodies
+            }
+
+            if ('POST' !== $method) {
+                $curlopts[CURLOPT_UPLOAD] = true;
+            }
+        } elseif ('' !== $body) {
+            $curlopts[CURLOPT_POSTFIELDS] = $body;
+        }
+
+        if ($options['peer_fingerprint']) {
+            if (!isset($options['peer_fingerprint']['pin-sha256'])) {
+                throw new TransportException(__CLASS__.' supports only "pin-sha256" fingerprints.');
+            }
+
+            $curlopts[CURLOPT_PINNEDPUBLICKEY] = 'sha256//'.implode(';sha256//', $options['peer_fingerprint']['pin-sha256']);
+        }
+
+        if ($options['bindto']) {
+            $curlopts[file_exists($options['bindto']) ? CURLOPT_UNIX_SOCKET_PATH : CURLOPT_INTERFACE] = $options['bindto'];
+        }
+
+        $ch = curl_init();
+
+        foreach ($curlopts as $opt => $value) {
+            if (null !== $value && !curl_setopt($ch, $opt, $value) && CURLOPT_CERTINFO !== $opt) {
+                $constants = array_filter(get_defined_constants(), static function ($v, $k) use ($opt) {
+                    return $v === $opt && 'C' === $k[0] && (0 === strpos($k, 'CURLOPT_') || 0 === strpos($k, 'CURLINFO_'));
+                }, ARRAY_FILTER_USE_BOTH);
+
+                throw new TransportException(sprintf('Curl option "%s" is not supported.', key($constants) ?? $opt));
+            }
+        }
+
+        return new CurlResponse($this->multi, $ch, $options, self::createRedirectResolver($options, $host));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stream($responses, float $timeout = null): ResponseStreamInterface
+    {
+        if ($responses instanceof CurlResponse) {
+            $responses = [$responses];
+        } elseif (!\is_iterable($responses)) {
+            throw new \TypeError(sprintf('%s() expects parameter 1 to be an iterable of CurlResponse objects, %s given.', __METHOD__, \is_object($responses) ? \get_class($responses) : \gettype($responses)));
+        }
+
+        while (CURLM_CALL_MULTI_PERFORM === curl_multi_exec($this->multi->handle, $active));
+
+        return new ResponseStream(CurlResponse::stream($responses, $timeout));
+    }
+
+    public function __destruct()
+    {
+        $this->multi->pushedResponses = [];
+        if (\defined('CURLMOPT_PUSHFUNCTION')) {
+            curl_multi_setopt($this->multi->handle, CURLMOPT_PUSHFUNCTION, null);
+        }
+    }
+
+    private static function handlePush($parent, $pushed, array $rawHeaders, \stdClass $multi): int
+    {
+        $headers = [];
+
+        foreach ($rawHeaders as $h) {
+            if (false !== $i = strpos($h, ':', 1)) {
+                $headers[substr($h, 0, $i)] = substr($h, 1 + $i);
+            }
+        }
+
+        if ('GET' !== $headers[':method'] || isset($headers['range'])) {
+            return CURL_PUSH_DENY;
+        }
+
+        $url = $headers[':scheme'].'://'.$headers[':authority'];
+
+        // curl before 7.65 doesn't validate the pushed ":authority" header,
+        // but this is a MUST in the HTTP/2 RFC; let's restrict pushes to the original host,
+        // ignoring domains mentioned as alt-name in the certificate for now (same as curl).
+        if (0 !== strpos(curl_getinfo($parent, CURLINFO_EFFECTIVE_URL), $url.'/')) {
+            return CURL_PUSH_DENY;
+        }
+
+        $multi->pushedResponses[$url.$headers[':path']] = [
+            new CurlResponse($multi, $pushed),
+            [
+                $headers['authorization'] ?? null,
+                $headers['cookie'] ?? null,
+                $headers['x-requested-with'] ?? null,
+                null,
+            ],
+        ];
+
+        return CURL_PUSH_OK;
+    }
+
+    /**
+     * Wraps the request's body callback to allow it to return strings longer than curl requested.
+     */
+    private static function readRequestBody(int $length, \Closure $body, string &$buffer, bool &$eof): string
+    {
+        if (!$eof && \strlen($buffer) < $length) {
+            if (!\is_string($data = $body($length))) {
+                throw new TransportException(sprintf('The return value of the "body" option callback must be a string, %s returned.', \gettype($data)));
+            }
+
+            $buffer .= $data;
+            $eof = '' === $data;
+        }
+
+        $data = substr($buffer, 0, $length);
+        $buffer = substr($buffer, $length);
+
+        return $data;
+    }
+
+    /**
+     * Resolves relative URLs on redirects and deals with authentication headers.
+     *
+     * Work around CVE-2018-1000007: Authorization and Cookie headers should not follow redirects - fixed in Curl 7.64
+     */
+    private static function createRedirectResolver(array $options, string $host): \Closure
+    {
+        $redirectHeaders = [];
+        if (0 < $options['max_redirects']) {
+            $redirectHeaders['host'] = $host;
+            $redirectHeaders['with_auth'] = $redirectHeaders['no_auth'] = array_filter($options['raw_headers'], static function ($h) {
+                return 0 !== stripos($h, 'Host:');
+            });
+
+            if (isset($options['headers']['authorization']) || isset($options['headers']['cookie'])) {
+                $redirectHeaders['no_auth'] = array_filter($options['raw_headers'], static function ($h) {
+                    return 0 !== stripos($h, 'Authorization:') && 0 !== stripos($h, 'Cookie:');
+                });
+            }
+        }
+
+        return static function ($ch, string $location) use ($redirectHeaders) {
+            if ($host = parse_url($location, PHP_URL_HOST)) {
+                $rawHeaders = $redirectHeaders['host'] === $host ? $redirectHeaders['with_auth'] : $redirectHeaders['no_auth'];
+                curl_setopt($ch, CURLOPT_HTTPHEADER, $rawHeaders);
+            }
+
+            $url = self::parseUrl(curl_getinfo($ch, CURLINFO_EFFECTIVE_URL));
+
+            return implode('', self::resolveUrl(self::parseUrl($location), $url));
+        };
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/ClientException.php b/src/Symfony/Component/HttpClient/Exception/ClientException.php
new file mode 100644
index 0000000000..3eb997432b
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/ClientException.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\Exception\ClientExceptionInterface;
+
+/**
+ * Represents a 4xx response.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class ClientException extends \RuntimeException implements ClientExceptionInterface
+{
+    use HttpExceptionTrait;
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/HttpExceptionTrait.php b/src/Symfony/Component/HttpClient/Exception/HttpExceptionTrait.php
new file mode 100644
index 0000000000..48f7b880eb
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/HttpExceptionTrait.php
@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\ResponseInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+trait HttpExceptionTrait
+{
+    public function __construct(ResponseInterface $response)
+    {
+        $code = $response->getInfo('http_code');
+        $url = $response->getInfo('url');
+        $message = sprintf('HTTP %d returned for URL "%s".', $code, $url);
+
+        foreach (array_reverse($response->getInfo('raw_headers')) as $h) {
+            if (0 === strpos($h, 'HTTP/')) {
+                $message = sprintf('%s returned for URL "%s".', $h, $url);
+                break;
+            }
+        }
+
+        parent::__construct($message, $code);
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/InvalidArgumentException.php b/src/Symfony/Component/HttpClient/Exception/InvalidArgumentException.php
new file mode 100644
index 0000000000..59afbd6ad0
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/InvalidArgumentException.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class InvalidArgumentException extends \InvalidArgumentException implements TransportExceptionInterface
+{
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/RedirectionException.php b/src/Symfony/Component/HttpClient/Exception/RedirectionException.php
new file mode 100644
index 0000000000..1c62f973b8
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/RedirectionException.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\Exception\RedirectionExceptionInterface;
+
+/**
+ * Represents a 3xx response.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class RedirectionException extends \RuntimeException implements RedirectionExceptionInterface
+{
+    use HttpExceptionTrait;
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/ServerException.php b/src/Symfony/Component/HttpClient/Exception/ServerException.php
new file mode 100644
index 0000000000..7b91de4865
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/ServerException.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\Exception\ServerExceptionInterface;
+
+/**
+ * Represents a 5xx response.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class ServerException extends \RuntimeException implements ServerExceptionInterface
+{
+    use HttpExceptionTrait;
+}
diff --git a/src/Symfony/Component/HttpClient/Exception/TransportException.php b/src/Symfony/Component/HttpClient/Exception/TransportException.php
new file mode 100644
index 0000000000..85606aa3b8
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Exception/TransportException.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Exception;
+
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class TransportException extends \RuntimeException implements TransportExceptionInterface
+{
+}
diff --git a/src/Symfony/Component/HttpClient/HttpClient.php b/src/Symfony/Component/HttpClient/HttpClient.php
new file mode 100644
index 0000000000..6d680d9b49
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/HttpClient.php
@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * A factory to instantiate the best possible HTTP client for the runtime.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+final class HttpClient
+{
+    /**
+     * @param array $defaultOptions     Default requests' options
+     * @param int   $maxHostConnections The maximum number of connections to a single host
+     *
+     * @see HttpClientInterface::OPTIONS_DEFAULTS for available options
+     */
+    public static function create(array $defaultOptions = [], int $maxHostConnections = 6): HttpClientInterface
+    {
+        if (\extension_loaded('curl')) {
+            return new CurlHttpClient($defaultOptions, $maxHostConnections);
+        }
+
+        return new NativeHttpClient($defaultOptions, $maxHostConnections);
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/HttpClientTrait.php b/src/Symfony/Component/HttpClient/HttpClientTrait.php
new file mode 100644
index 0000000000..ab9bbca5c9
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/HttpClientTrait.php
@@ -0,0 +1,457 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Symfony\Component\HttpClient\Exception\InvalidArgumentException;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * Provides the common logic from writing HttpClientInterface implementations.
+ *
+ * All methods are static to prevent implementers from creating memory leaks via circular references.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+trait HttpClientTrait
+{
+    private static $CHUNK_SIZE = 16372;
+
+    /**
+     * Validates and normalizes method, URL and options, and merges them with defaults.
+     *
+     * @throws InvalidArgumentException When a not-supported option is found
+     */
+    private static function prepareRequest(?string $method, ?string $url, array $options, array $defaultOptions = [], bool $allowExtraOptions = false): array
+    {
+        if (null !== $method && \strlen($method) !== strspn($method, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')) {
+            throw new InvalidArgumentException(sprintf('Invalid HTTP method "%s", only uppercase letters are accepted.', $method));
+        }
+
+        $options = self::mergeDefaultOptions($options, $defaultOptions, $allowExtraOptions);
+
+        if (isset($options['json'])) {
+            $options['body'] = self::jsonEncode($options['json']);
+            $options['headers']['content-type'] = $options['headers']['content-type'] ?? ['application/json'];
+        }
+
+        if (isset($options['body'])) {
+            $options['body'] = self::normalizeBody($options['body']);
+        }
+
+        if (isset($options['peer_fingerprint'])) {
+            $options['peer_fingerprint'] = self::normalizePeerFingerprint($options['peer_fingerprint']);
+        }
+
+        // Compute raw headers
+        $rawHeaders = $headers = [];
+
+        foreach ($options['headers'] as $name => $values) {
+            foreach ($values as $value) {
+                $rawHeaders[] = $name.': '.$headers[$name][] = $value = (string) $value;
+
+                if (\strlen($value) !== strcspn($value, "\r\n\0")) {
+                    throw new InvalidArgumentException(sprintf('Invalid header value: CR/LF/NUL found in "%s".', $value));
+                }
+            }
+        }
+
+        // Validate on_progress
+        if (!\is_callable($onProgress = $options['on_progress'] ?? 'var_dump')) {
+            throw new InvalidArgumentException(sprintf('Option "on_progress" must be callable, %s given.', \is_object($onProgress) ? \get_class($onProgress) : \gettype($onProgress)));
+        }
+
+        if (!\is_string($options['auth'] ?? '')) {
+            throw new InvalidArgumentException(sprintf('Option "auth" must be string, %s given.', \gettype($options['auth'])));
+        }
+
+        if (null !== $url) {
+            // Merge auth with headers
+            if (($options['auth'] ?? false) && !($headers['authorization'] ?? false)) {
+                $rawHeaders[] = 'authorization: '.$headers['authorization'][] = 'Basic '.base64_encode($options['auth']);
+            }
+
+            $options['raw_headers'] = $rawHeaders;
+            unset($options['auth']);
+
+            // Parse base URI
+            if (\is_string($options['base_uri'])) {
+                $options['base_uri'] = self::parseUrl($options['base_uri']);
+            }
+
+            // Validate and resolve URL
+            $url = self::parseUrl($url, $options['query']);
+            $url = self::resolveUrl($url, $options['base_uri'], $defaultOptions['query'] ?? []);
+        }
+
+        // Finalize normalization of options
+        $options['headers'] = $headers;
+        $options['http_version'] = (string) ($options['http_version'] ?? '');
+        $options['timeout'] = (float) ($options['timeout'] ?? ini_get('default_socket_timeout'));
+
+        return [$url, $options];
+    }
+
+    /**
+     * @throws InvalidArgumentException When an invalid option is found
+     */
+    private static function mergeDefaultOptions(array $options, array $defaultOptions, bool $allowExtraOptions = false): array
+    {
+        $options['headers'] = self::normalizeHeaders($options['headers'] ?? []);
+
+        if ($defaultOptions['headers'] ?? false) {
+            $options['headers'] += self::normalizeHeaders($defaultOptions['headers']);
+        }
+
+        if ($options['resolve'] ?? false) {
+            $options['resolve'] = array_change_key_case($options['resolve']);
+        }
+
+        // Option "query" is never inherited from defaults
+        $options['query'] = $options['query'] ?? [];
+
+        $options += $defaultOptions;
+
+        if ($defaultOptions['resolve'] ?? false) {
+            $options['resolve'] += array_change_key_case($defaultOptions['resolve']);
+        }
+
+        if ($allowExtraOptions || !$defaultOptions) {
+            return $options;
+        }
+
+        // Look for unsupported options
+        foreach ($options as $name => $v) {
+            if (\array_key_exists($name, $defaultOptions)) {
+                continue;
+            }
+
+            $alternatives = [];
+
+            foreach ($defaultOptions as $key => $v) {
+                if (levenshtein($name, $key) <= \strlen($name) / 3 || false !== strpos($key, $name)) {
+                    $alternatives[] = $key;
+                }
+            }
+
+            throw new InvalidArgumentException(sprintf('Unsupported option "%s" passed to %s, did you mean "%s"?', $name, __CLASS__, implode('", "', $alternatives ?: array_keys($defaultOptions))));
+        }
+
+        return $options;
+    }
+
+    /**
+     * Normalizes headers by putting their names as lowercased keys.
+     *
+     * @return string[][]
+     */
+    private static function normalizeHeaders(array $headers): array
+    {
+        $normalizedHeaders = [];
+
+        foreach ($headers as $name => $values) {
+            if (\is_int($name)) {
+                [$name, $values] = explode(':', $values, 2);
+                $values = [ltrim($values)];
+            } elseif (!\is_iterable($values)) {
+                $values = (array) $values;
+            }
+
+            $normalizedHeaders[$name = strtolower($name)] = [];
+
+            foreach ($values as $value) {
+                $normalizedHeaders[$name][] = $value;
+            }
+        }
+
+        return $normalizedHeaders;
+    }
+
+    /**
+     * @param array|string|resource|\Traversable|\Closure $body
+     *
+     * @return string|resource|\Closure
+     *
+     * @throws InvalidArgumentException When an invalid body is passed
+     */
+    private static function normalizeBody($body)
+    {
+        if (\is_array($body)) {
+            return http_build_query($body, '', '&', PHP_QUERY_RFC1738);
+        }
+
+        if ($body instanceof \Traversable) {
+            $body = function () use ($body) { yield from $body; };
+        }
+
+        if ($body instanceof \Closure) {
+            $r = new \ReflectionFunction($body);
+            $body = $r->getClosure();
+
+            if ($r->isGenerator()) {
+                $body = $body(self::$CHUNK_SIZE);
+                $body = function () use ($body) {
+                    $chunk = $body->valid() ? $body->current() : '';
+                    $body->next();
+
+                    return $chunk;
+                };
+            }
+
+            return $body;
+        }
+
+        if (!\is_string($body) && !\is_array(@stream_get_meta_data($body))) {
+            throw new InvalidArgumentException(sprintf('Option "body" must be string, stream resource, iterable or callable, %s given.', \is_resource($body) ? get_resource_type($body) : \gettype($body)));
+        }
+
+        return $body;
+    }
+
+    /**
+     * @param string|string[] $fingerprint
+     *
+     * @throws InvalidArgumentException When an invalid fingerprint is passed
+     */
+    private static function normalizePeerFingerprint($fingerprint): array
+    {
+        if (\is_string($fingerprint)) {
+            switch (\strlen($fingerprint = str_replace(':', '', $fingerprint))) {
+                case 32: $fingerprint = ['md5' => $fingerprint]; break;
+                case 40: $fingerprint = ['sha1' => $fingerprint]; break;
+                case 44: $fingerprint = ['pin-sha256' => [$fingerprint]]; break;
+                case 64: $fingerprint = ['sha256' => $fingerprint]; break;
+                default: throw new InvalidArgumentException(sprintf('Cannot auto-detect fingerprint algorithm for "%s".', $fingerprint));
+            }
+        } elseif (\is_array($fingerprint)) {
+            foreach ($fingerprint as $algo => $hash) {
+                $fingerprint[$algo] = 'pin-sha256' === $algo ? (array) $hash : str_replace(':', '', $hash);
+            }
+        } else {
+            throw new InvalidArgumentException(sprintf('Option "peer_fingerprint" must be string or array, %s given.', \gettype($body)));
+        }
+
+        return $fingerprint;
+    }
+
+    /**
+     * @param array|\JsonSerializable $value
+     *
+     * @throws InvalidArgumentException When the value cannot be json-encoded
+     */
+    private static function jsonEncode($value, int $flags = null, int $maxDepth = 512): string
+    {
+        $flags = $flags ?? (JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT | JSON_PRESERVE_ZERO_FRACTION);
+
+        if (!\is_array($value) && !$value instanceof \JsonSerializable) {
+            throw new InvalidArgumentException(sprintf('Option "json" must be array or JsonSerializable, %s given.', __CLASS__, \is_object($value) ? \get_class($value) : \gettype($value)));
+        }
+
+        try {
+            $value = json_encode($value, $flags | (\PHP_VERSION_ID >= 70300 ? JSON_THROW_ON_ERROR : 0), $maxDepth);
+        } catch (\JsonException $e) {
+            throw new InvalidArgumentException(sprintf('Invalid value for "json" option: %s.', $e->getMessage()));
+        }
+
+        if (\PHP_VERSION_ID < 70300 && JSON_ERROR_NONE !== json_last_error() && (false === $value || !($flags & JSON_PARTIAL_OUTPUT_ON_ERROR))) {
+            throw new InvalidArgumentException(sprintf('Invalid value for "json" option: %s.', json_last_error_msg()));
+        }
+
+        return $value;
+    }
+
+    /**
+     * Resolves a URL against a base URI.
+     *
+     * @see https://tools.ietf.org/html/rfc3986#section-5.2.2
+     *
+     * @throws InvalidArgumentException When an invalid URL is passed
+     */
+    private static function resolveUrl(array $url, ?array $base, array $queryDefaults = []): array
+    {
+        if (null !== $base && '' === ($base['scheme'] ?? '').($base['authority'] ?? '')) {
+            throw new InvalidArgumentException(sprintf('Invalid "base_uri" option: host or scheme is missing in "%s".', implode('', $base)));
+        }
+
+        if (null === $base && '' === $url['scheme'].$url['authority']) {
+            throw new InvalidArgumentException(sprintf('Invalid URL: no "base_uri" option was provided and host or scheme is missing in "%s".', implode('', $url)));
+        }
+
+        if (null !== $url['scheme']) {
+            $url['path'] = self::removeDotSegments($url['path'] ?? '');
+        } else {
+            if (null !== $url['authority']) {
+                $url['path'] = self::removeDotSegments($url['path'] ?? '');
+            } else {
+                if (null === $url['path']) {
+                    $url['path'] = $base['path'];
+                    $url['query'] = $url['query'] ?? $base['query'];
+                } else {
+                    if ('/' !== $url['path'][0]) {
+                        if (null === $base['path']) {
+                            $url['path'] = '/'.$url['path'];
+                        } else {
+                            $segments = explode('/', $base['path']);
+                            array_splice($segments, -1, 1, [$url['path']]);
+                            $url['path'] = implode('/', $segments);
+                        }
+                    }
+
+                    $url['path'] = self::removeDotSegments($url['path']);
+                }
+
+                $url['authority'] = $base['authority'];
+
+                if ($queryDefaults) {
+                    $url['query'] = '?'.self::mergeQueryString(substr($url['query'] ?? '', 1), $queryDefaults, false);
+                }
+            }
+
+            $url['scheme'] = $base['scheme'];
+        }
+
+        if ('' === ($url['path'] ?? '')) {
+            $url['path'] = '/';
+        }
+
+        return $url;
+    }
+
+    /**
+     * Parses a URL and fixes its encoding if needed.
+     *
+     * @throws InvalidArgumentException When an invalid URL is passed
+     */
+    private static function parseUrl(string $url, array $query = [], array $allowedSchemes = ['http' => 80, 'https' => 443]): array
+    {
+        if (false === $parts = parse_url($url)) {
+            throw new InvalidArgumentException(sprintf('Malformed URL "%s".', $url));
+        }
+
+        if ($query) {
+            $parts['query'] = self::mergeQueryString($parts['query'] ?? null, $query, true);
+        }
+
+        $port = $parts['port'] ?? 0;
+
+        if (null !== $scheme = $parts['scheme'] ?? null) {
+            if (!isset($allowedSchemes[$scheme = strtolower($scheme)])) {
+                throw new InvalidArgumentException(sprintf('Unsupported scheme in "%s".', $url));
+            }
+
+            $port = $allowedSchemes[$scheme] === $port ? 0 : $port;
+            $scheme .= ':';
+        }
+
+        if (null !== $host = $parts['host'] ?? null) {
+            if (!\defined('INTL_IDNA_VARIANT_UTS46') && preg_match('/[\x80-\xFF]/', $host)) {
+                throw new InvalidArgumentException(sprintf('Unsupported IDN "%s", try enabling the "intl" PHP extension or running "composer require symfony/polyfill-intl-idn".', $host));
+            }
+
+            if (false === $host = \defined('INTL_IDNA_VARIANT_UTS46') ? idn_to_ascii($host, IDNA_DEFAULT, INTL_IDNA_VARIANT_UTS46) : strtolower($host)) {
+                throw new InvalidArgumentException(sprintf('Unsupported host in "%s".', $url));
+            }
+
+            $host .= $port ? ':'.$port : '';
+        }
+
+        foreach (['user', 'pass', 'path', 'query', 'fragment'] as $part) {
+            if (!isset($parts[$part])) {
+                continue;
+            }
+
+            if (false !== strpos($parts[$part], '%')) {
+                // https://tools.ietf.org/html/rfc3986#section-2.3
+                $parts[$part] = preg_replace_callback('/%(?:2[DE]|3[0-9]|[46][1-9A-F]|5F|[57][0-9A]|7E)++/i', function ($m) { return rawurldecode($m[0]); }, $parts[$part]);
+            }
+
+            // https://tools.ietf.org/html/rfc3986#section-3.3
+            $parts[$part] = preg_replace_callback("#[^-A-Za-z0-9._~!$&/'()*+,;=:@%]++#", function ($m) { return rawurlencode($m[0]); }, $parts[$part]);
+        }
+
+        return [
+            'scheme' => $scheme,
+            'authority' => null !== $host ? '//'.(isset($parts['user']) ? $parts['user'].(isset($parts['pass']) ? ':'.$parts['pass'] : '').'@' : '').$host : null,
+            'path' => isset($parts['path'][0]) ? $parts['path'] : null,
+            'query' => isset($parts['query']) ? '?'.$parts['query'] : null,
+            'fragment' => isset($parts['fragment']) ? '#'.$parts['fragment'] : null,
+        ];
+    }
+
+    /**
+     * Removes dot-segments from a path.
+     *
+     * @see https://tools.ietf.org/html/rfc3986#section-5.2.4
+     */
+    private static function removeDotSegments(string $path)
+    {
+        $result = '';
+
+        while (!\in_array($path, ['', '.', '..'], true)) {
+            if ('.' === $path[0] && (0 === strpos($path, $p = '../') || 0 === strpos($path, $p = './'))) {
+                $path = substr($path, \strlen($p));
+            } elseif ('/.' === $path || 0 === strpos($path, '/./')) {
+                $path = substr_replace($path, '/', 0, 3);
+            } elseif ('/..' === $path || 0 === strpos($path, '/../')) {
+                $i = strrpos($result, '/');
+                $result = $i ? substr($result, 0, $i) : '';
+                $path = substr_replace($path, '/', 0, 4);
+            } else {
+                $i = strpos($path, '/', 1) ?: \strlen($path);
+                $result .= substr($path, 0, $i);
+                $path = substr($path, $i);
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * Merges and encodes a query array with a query string.
+     *
+     * @throws InvalidArgumentException When an invalid query-string value is passed
+     */
+    private static function mergeQueryString(?string $queryString, array $queryArray, bool $replace): ?string
+    {
+        if (!$queryArray) {
+            return $queryString;
+        }
+
+        $query = [];
+
+        if (null !== $queryString) {
+            foreach (explode('&', $queryString) as $v) {
+                if ('' !== $v) {
+                    $k = urldecode(explode('=', $v, 2)[0]);
+                    $query[$k] = (isset($query[$k]) ? $query[$k].'&' : '').$v;
+                }
+            }
+        }
+
+        foreach ($queryArray as $k => $v) {
+            if (is_scalar($v)) {
+                $queryArray[$k] = rawurlencode($k).'='.rawurlencode($v);
+            } elseif (null === $v) {
+                unset($queryArray[$k]);
+
+                if ($replace) {
+                    unset($query[$k]);
+                }
+            } else {
+                throw new InvalidArgumentException(sprintf('Unsupported value for query parameter "%s": scalar or null expected, %s given.', $k, \gettype($v)));
+            }
+        }
+
+        return implode('&', $replace ? array_replace($query, $queryArray) : ($query + $queryArray));
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/HttpOptions.php b/src/Symfony/Component/HttpClient/HttpOptions.php
new file mode 100644
index 0000000000..ce85eaf274
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/HttpOptions.php
@@ -0,0 +1,299 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * A helper providing autocompletion for available options.
+ *
+ * @see HttpClientInterface for a description of each options.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+class HttpOptions
+{
+    private $options = [];
+
+    public function toArray(): array
+    {
+        return $this->options;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setAuth(string $userinfo)
+    {
+        $this->options['auth'] = $userinfo;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setQuery(array $query)
+    {
+        $this->options['query'] = $query;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setHeaders(iterable $headers)
+    {
+        $this->options['headers'] = $headers;
+
+        return $this;
+    }
+
+    /**
+     * @param array|string|resource|\Traversable|\Closure $body
+     *
+     * @return $this
+     */
+    public function setBody($body)
+    {
+        $this->options['body'] = $body;
+
+        return $this;
+    }
+
+    /**
+     * @param array|\JsonSerializable $json
+     *
+     * @return $this
+     */
+    public function setJson($json)
+    {
+        $this->options['json'] = $json;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setUserData($data)
+    {
+        $this->options['user_data'] = $data;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setMaxRedirects(int $max)
+    {
+        $this->options['max_redirects'] = $max;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setHttpVersion(string $version)
+    {
+        $this->options['http_version'] = $version;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setBaseUri(string $uri)
+    {
+        $this->options['base_uri'] = $uri;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function buffer(bool $buffer)
+    {
+        $this->options['buffer'] = $buffer;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setOnProgress(callable $callback)
+    {
+        $this->options['on_progress'] = $callback;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function resolve(array $hostIps)
+    {
+        $this->options['resolve'] = $hostIps;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setProxy(string $proxy)
+    {
+        $this->options['proxy'] = $proxy;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setNoProxy(string $noProxy)
+    {
+        $this->options['no_proxy'] = $noProxy;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setTimeout(float $timeout)
+    {
+        $this->options['timeout'] = $timeout;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function bindTo(string $bindto)
+    {
+        $this->options['bindto'] = $bindto;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function verifyPeer(bool $verify)
+    {
+        $this->options['verify_peer'] = $verify;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function verifyHost(bool $verify)
+    {
+        $this->options['verify_host'] = $verify;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setCaFile(string $cafile)
+    {
+        $this->options['cafile'] = $cafile;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setCaPath(string $capath)
+    {
+        $this->options['capath'] = $capath;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setLocalCert(string $cert)
+    {
+        $this->options['local_cert'] = $cert;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setLocalPk(string $pk)
+    {
+        $this->options['local_pk'] = $pk;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setPassphrase(string $passphrase)
+    {
+        $this->options['passphrase'] = $passphrase;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setCiphers(string $ciphers)
+    {
+        $this->options['ciphers'] = $ciphers;
+
+        return $this;
+    }
+
+    /**
+     * @param string|array $fingerprint
+     *
+     * @return $this
+     */
+    public function setPeerFingerprint($fingerprint)
+    {
+        $this->options['peer_fingerprint'] = $fingerprint;
+
+        return $this;
+    }
+
+    /**
+     * @return $this
+     */
+    public function capturePeerCertChain(bool $capture)
+    {
+        $this->options['capture_peer_cert_chain'] = $capture;
+
+        return $this;
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/LICENSE b/src/Symfony/Component/HttpClient/LICENSE
new file mode 100644
index 0000000000..3f853aaf35
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2018-2019 Fabien Potencier
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/src/Symfony/Component/HttpClient/NativeHttpClient.php b/src/Symfony/Component/HttpClient/NativeHttpClient.php
new file mode 100644
index 0000000000..c79f9af7b3
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/NativeHttpClient.php
@@ -0,0 +1,420 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Symfony\Component\HttpClient\Exception\TransportException;
+use Symfony\Component\HttpClient\Response\NativeResponse;
+use Symfony\Component\HttpClient\Response\ResponseStream;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+use Symfony\Contracts\HttpClient\ResponseStreamInterface;
+
+/**
+ * A portable implementation of the HttpClientInterface contracts based on PHP stream wrappers.
+ *
+ * PHP stream wrappers are able to fetch response bodies concurrently,
+ * but each request is opened synchronously.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+final class NativeHttpClient implements HttpClientInterface
+{
+    use HttpClientTrait;
+
+    private $defaultOptions = self::OPTIONS_DEFAULTS;
+    private $multi;
+
+    /**
+     * @param array $defaultOptions     Default requests' options
+     * @param int   $maxHostConnections The maximum number of connections to open
+     *
+     * @see HttpClientInterface::OPTIONS_DEFAULTS for available options
+     */
+    public function __construct(array $defaultOptions = [], int $maxHostConnections = 6)
+    {
+        if ($defaultOptions) {
+            [, $this->defaultOptions] = self::prepareRequest(null, null, $defaultOptions, self::OPTIONS_DEFAULTS);
+        }
+
+        // Use an internal stdClass object to share state between the client and its responses
+        $this->multi = (object) [
+            'openHandles' => [],
+            'handlesActivity' => [],
+            'pendingResponses' => [],
+            'maxHostConnections' => $maxHostConnections,
+            'responseCount' => 0,
+            'dnsCache' => [],
+            'handles' => [],
+            'sleep' => false,
+            'id' => random_int(PHP_INT_MIN, PHP_INT_MAX),
+        ];
+    }
+
+    /**
+     * @see HttpClientInterface::OPTIONS_DEFAULTS for available options
+     *
+     * {@inheritdoc}
+     */
+    public function request(string $method, string $url, array $options = []): ResponseInterface
+    {
+        [$url, $options] = self::prepareRequest($method, $url, $options, $this->defaultOptions);
+
+        if ($options['bindto'] && file_exists($options['bindto'])) {
+            throw new TransportException(__CLASS__.' cannot bind to local Unix sockets, use e.g. CurlHttpClient instead.');
+        }
+
+        $options['body'] = self::getBodyAsString($options['body']);
+
+        if ('' !== $options['body'] && 'POST' === $method && !isset($options['headers']['content-type'])) {
+            $options['raw_headers'][] = 'content-type: application/x-www-form-urlencoded';
+        }
+
+        if ($gzipEnabled = \extension_loaded('zlib') && !isset($options['headers']['accept-encoding'])) {
+            // gzip is the most widely available algo, no need to deal with deflate
+            $options['raw_headers'][] = 'accept-encoding: gzip';
+        }
+
+        if ($options['peer_fingerprint']) {
+            if (isset($options['peer_fingerprint']['pin-sha256']) && 1 === \count($options['peer_fingerprint'])) {
+                throw new TransportException(__CLASS__.' cannot verify "pin-sha256" fingerprints, please provide a "sha256" one.');
+            }
+
+            unset($options['peer_fingerprint']['pin-sha256']);
+        }
+
+        $info = [
+            'raw_headers' => [],
+            'url' => $url,
+            'error' => null,
+            'http_code' => 0,
+            'redirect_count' => 0,
+            'start_time' => 0.0,
+            'fopen_time' => 0.0,
+            'connect_time' => 0.0,
+            'redirect_time' => 0.0,
+            'starttransfer_time' => 0.0,
+            'total_time' => 0.0,
+            'namelookup_time' => 0.0,
+            'size_upload' => 0,
+            'size_download' => 0,
+            'size_body' => \strlen($options['body']),
+            'primary_ip' => '',
+            'primary_port' => 'http:' === $url['scheme'] ? 80 : 443,
+        ];
+
+        if ($onProgress = $options['on_progress']) {
+            // Memoize the last progress to ease calling the callback periodically when no network transfer happens
+            $lastProgress = [0, 0];
+            $onProgress = static function (...$progress) use ($onProgress, &$lastProgress, &$info) {
+                $progressInfo = $info;
+                $progressInfo['url'] = implode('', $info['url']);
+                unset($progressInfo['fopen_time'], $progressInfo['size_body']);
+
+                if ($progress && -1 === $progress[0]) {
+                    // Response completed
+                    $lastProgress[0] = max($lastProgress);
+                } else {
+                    $lastProgress = $progress ?: $lastProgress;
+                }
+
+                $onProgress($lastProgress[0], $lastProgress[1], $progressInfo);
+            };
+        }
+
+        // Always register a notification callback to compute live stats about the response
+        $notification = static function (int $code, int $severity, ?string $msg, int $msgCode, int $dlNow, int $dlSize) use ($onProgress, &$info) {
+            $now = microtime(true);
+            $info['total_time'] = $now - $info['start_time'];
+
+            if (STREAM_NOTIFY_PROGRESS === $code) {
+                $info['size_upload'] += $dlNow ? 0 : $info['size_body'];
+                $info['size_download'] = $dlNow;
+            } elseif (STREAM_NOTIFY_CONNECT === $code) {
+                $info['connect_time'] += $now - $info['fopen_time'];
+            } else {
+                return;
+            }
+
+            if ($onProgress) {
+                $onProgress($dlNow, $dlSize);
+            }
+        };
+
+        if ($options['resolve']) {
+            $this->multi->dnsCache = $options['resolve'] + $this->multi->dnsCache;
+        }
+
+        [$host, $port, $url['authority']] = self::dnsResolve($url, $this->multi, $info, $onProgress);
+
+        if (!isset($options['headers']['host'])) {
+            $options['raw_headers'][] = 'host: '.$host.$port;
+        }
+
+        $context = [
+            'http' => [
+                'protocol_version' => $options['http_version'] ?: '1.1',
+                'method' => $method,
+                'content' => $options['body'],
+                'ignore_errors' => true,
+                'user_agent' => 'Symfony HttpClient/Native',
+                'curl_verify_ssl_peer' => $options['verify_peer'],
+                'curl_verify_ssl_host' => $options['verify_host'],
+                'auto_decode' => false, // Disable dechunk filter, it's incompatible with stream_select()
+                'timeout' => $options['timeout'],
+                'follow_location' => false, // We follow redirects ourselves - the native logic is too limited
+            ],
+            'ssl' => array_filter([
+                'peer_name' => $host,
+                'verify_peer' => $options['verify_peer'],
+                'verify_peer_name' => $options['verify_host'],
+                'cafile' => $options['cafile'],
+                'capath' => $options['capath'],
+                'local_cert' => $options['local_cert'],
+                'local_pk' => $options['local_pk'],
+                'passphrase' => $options['passphrase'],
+                'ciphers' => $options['ciphers'],
+                'peer_fingerprint' => $options['peer_fingerprint'],
+                'capture_peer_cert_chain' => $options['capture_peer_cert_chain'],
+                'allow_self_signed' => (bool) $options['peer_fingerprint'],
+                'SNI_enabled' => true,
+                'disable_compression' => true,
+            ], static function ($v) { return null !== $v; }),
+            'socket' => [
+                'bindto' => $options['bindto'],
+                'tcp_nodelay' => true,
+            ],
+        ];
+
+        $proxy = self::getProxy($options['proxy'], $url);
+        $noProxy = $noProxy ?? $_SERVER['no_proxy'] ?? $_SERVER['NO_PROXY'] ?? '';
+        $noProxy = $noProxy ? preg_split('/[\s,]+/', $noProxy) : [];
+
+        $resolveRedirect = self::createRedirectResolver($options, $host, $proxy, $noProxy, $info, $onProgress);
+        $context = stream_context_create($context, ['notification' => $notification]);
+        self::configureHeadersAndProxy($context, $host, $options['raw_headers'], $proxy, $noProxy);
+
+        return new NativeResponse($this->multi, $context, implode('', $url), $options, $gzipEnabled, $info, $resolveRedirect, $onProgress);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stream($responses, float $timeout = null): ResponseStreamInterface
+    {
+        if ($responses instanceof NativeResponse) {
+            $responses = [$responses];
+        } elseif (!\is_iterable($responses)) {
+            throw new \TypeError(sprintf('%s() expects parameter 1 to be an iterable of NativeResponse objects, %s given.', __METHOD__, \is_object($responses) ? \get_class($responses) : \gettype($responses)));
+        }
+
+        return new ResponseStream(NativeResponse::stream($responses, $timeout));
+    }
+
+    private static function getBodyAsString($body): string
+    {
+        if (\is_resource($body)) {
+            return stream_get_contents($body);
+        }
+
+        if (!$body instanceof \Closure) {
+            return $body;
+        }
+
+        $result = '';
+
+        while ('' !== $data = $body(self::$CHUNK_SIZE)) {
+            if (!\is_string($data)) {
+                throw new TransportException(sprintf('Return value of the "body" option callback must be string, %s returned.', \gettype($data)));
+            }
+
+            $result .= $data;
+        }
+
+        return $result;
+    }
+
+    /**
+     * Loads proxy configuration from the same environment variables as curl when no proxy is explicitly set.
+     */
+    private static function getProxy(?string $proxy, array $url): ?array
+    {
+        if (null === $proxy) {
+            // Ignore HTTP_PROXY except on the CLI to work around httpoxy set of vulnerabilities
+            $proxy = $_SERVER['http_proxy'] ?? ('cli' === \PHP_SAPI ? $_SERVER['HTTP_PROXY'] ?? null : null) ?? $_SERVER['all_proxy'] ?? $_SERVER['ALL_PROXY'] ?? null;
+
+            if ('https:' === $url['scheme']) {
+                $proxy = $_SERVER['https_proxy'] ?? $_SERVER['HTTPS_PROXY'] ?? $proxy;
+            }
+        }
+
+        if (null === $proxy) {
+            return null;
+        }
+
+        $proxy = (parse_url($proxy) ?: []) + ['scheme' => 'http'];
+
+        if (!isset($proxy['host'])) {
+            throw new TransportException('Invalid HTTP proxy: host is missing.');
+        }
+
+        if ('http' === $proxy['scheme']) {
+            $proxyUrl = 'tcp://'.$proxy['host'].':'.($proxy['port'] ?? '80');
+        } elseif ('https' === $proxy['scheme']) {
+            $proxyUrl = 'ssl://'.$proxy['host'].':'.($proxy['port'] ?? '443');
+        } else {
+            throw new TransportException(sprintf('Unsupported proxy scheme "%s": "http" or "https" expected.', $proxy['scheme']));
+        }
+
+        return [
+            'url' => $proxyUrl,
+            'auth' => isset($proxy['user']) ? 'Basic '.base64_encode(rawurldecode($proxy['user']).':'.rawurldecode($proxy['pass'] ?? '')) : null,
+        ];
+    }
+
+    /**
+     * Resolves the IP of the host using the local DNS cache if possible.
+     */
+    private static function dnsResolve(array $url, \stdClass $multi, array &$info, ?\Closure $onProgress): array
+    {
+        if ($port = parse_url($url['authority'], PHP_URL_PORT) ?: '') {
+            $info['primary_port'] = $port;
+            $port = ':'.$port;
+        } else {
+            $info['primary_port'] = 'http:' === $url['scheme'] ? 80 : 443;
+        }
+
+        $host = parse_url($url['authority'], PHP_URL_HOST);
+
+        if (null === $ip = $multi->dnsCache[$host] ?? null) {
+            $now = microtime(true);
+
+            if (!$ip = gethostbynamel($host)) {
+                throw new TransportException(sprintf('Could not resolve host "%s".', $host));
+            }
+
+            $info['namelookup_time'] += microtime(true) - $now;
+            $multi->dnsCache[$host] = $ip = $ip[0];
+        }
+
+        $info['primary_ip'] = $ip;
+
+        if ($onProgress) {
+            // Notify DNS resolution
+            $onProgress();
+        }
+
+        return [$host, $port, substr_replace($url['authority'], $ip, -\strlen($host) - \strlen($port), \strlen($host))];
+    }
+
+    /**
+     * Handles redirects - the native logic is too buggy to be used.
+     */
+    private static function createRedirectResolver(array $options, string $host, ?array $proxy, array $noProxy, array &$info, ?\Closure $onProgress): \Closure
+    {
+        $redirectHeaders = [];
+        if (0 < $maxRedirects = $options['max_redirects']) {
+            $redirectHeaders = ['host' => $host];
+            $redirectHeaders['with_auth'] = $redirectHeaders['no_auth'] = array_filter($options['raw_headers'], static function ($h) {
+                return 0 !== stripos($h, 'Host:');
+            });
+
+            if (isset($options['headers']['authorization']) || isset($options['headers']['cookie'])) {
+                $redirectHeaders['no_auth'] = array_filter($options['raw_headers'], static function ($h) {
+                    return 0 !== stripos($h, 'Authorization:') && 0 !== stripos($h, 'Cookie:');
+                });
+            }
+        }
+
+        return static function (\stdClass $multi, int $statusCode, ?string $location, $context) use ($redirectHeaders, $proxy, $noProxy, &$info, $maxRedirects, $onProgress): ?string {
+            if (null === $location || $statusCode < 300 || 400 <= $statusCode) {
+                $info['redirect_url'] = null;
+
+                return null;
+            }
+
+            $url = self::resolveUrl(self::parseUrl($location), $info['url']);
+            $info['redirect_url'] = implode('', $url);
+
+            if ($info['redirect_count'] >= $maxRedirects) {
+                return null;
+            }
+
+            $now = microtime(true);
+            $info['url'] = $url;
+            ++$info['redirect_count'];
+            $info['redirect_time'] = $now - $info['start_time'];
+
+            // Do like curl and browsers: turn POST to GET on 301, 302 and 303
+            if (\in_array($statusCode, [301, 302, 303], true)) {
+                $options = stream_context_get_options($context)['http'];
+
+                if ('POST' === $options['method'] || 303 === $statusCode) {
+                    $options['method'] = 'HEAD' === $options['method'] ? 'HEAD' : 'GET';
+                    $options['content'] = '';
+                    $options['header'] = array_filter($options['header'], static function ($h) {
+                        return 0 !== stripos($h, 'Content-Length:') && 0 !== stripos($h, 'Content-Type:');
+                    });
+
+                    stream_context_set_option($context, ['http' => $options]);
+                }
+            }
+
+            [$host, $port, $url['authority']] = self::dnsResolve($url, $multi, $info, $onProgress);
+            stream_context_set_option($context, 'ssl', 'peer_name', $host);
+
+            if (false !== (parse_url($location, PHP_URL_HOST) ?? false)) {
+                // Authorization and Cookie headers MUST NOT follow except for the initial host name
+                $rawHeaders = $redirectHeaders['host'] === $host ? $redirectHeaders['with_auth'] : $redirectHeaders['no_auth'];
+                $rawHeaders[] = 'host: '.$host.$port;
+                self::configureHeadersAndProxy($context, $host, $rawHeaders, $proxy, $noProxy);
+            }
+
+            return implode('', $url);
+        };
+    }
+
+    private static function configureHeadersAndProxy($context, string $host, array $rawHeaders, ?array $proxy, array $noProxy)
+    {
+        if (null === $proxy) {
+            return stream_context_set_option($context, 'http', 'header', $rawHeaders);
+        }
+
+        // Matching "no_proxy" should follow the behavior of curl
+
+        foreach ($noProxy as $rule) {
+            if ('*' === $rule) {
+                return stream_context_set_option($context, 'http', 'header', $rawHeaders);
+            }
+
+            if ($host === $rule) {
+                return stream_context_set_option($context, 'http', 'header', $rawHeaders);
+            }
+
+            $rule = '.'.ltrim($rule, '.');
+
+            if (substr($host, -\strlen($rule)) === $rule) {
+                return stream_context_set_option($context, 'http', 'header', $rawHeaders);
+            }
+        }
+
+        stream_context_set_option($context, 'http', 'proxy', $proxy['url']);
+        stream_context_set_option($context, 'http', 'request_fulluri', true);
+
+        if (null !== $proxy['auth']) {
+            $rawHeaders[] = 'Proxy-Authorization: '.$proxy['auth'];
+        }
+
+        return stream_context_set_option($context, 'http', 'header', $rawHeaders);
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Psr18Client.php b/src/Symfony/Component/HttpClient/Psr18Client.php
new file mode 100644
index 0000000000..9c00940339
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Psr18Client.php
@@ -0,0 +1,109 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient;
+
+use Psr\Http\Client\ClientInterface;
+use Psr\Http\Client\NetworkExceptionInterface;
+use Psr\Http\Client\RequestExceptionInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseFactoryInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\StreamFactoryInterface;
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * An adapter to turn a Symfony HttpClientInterface into a PSR-18 ClientInterface.
+ *
+ * Run "composer require psr/http-client" to install the base ClientInterface. Run
+ * "composer require nyholm/psr7" to install an efficient implementation of response
+ * and stream factories with flex-provided autowiring aliases.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 4.3
+ */
+final class Psr18Client implements ClientInterface
+{
+    private $client;
+    private $responseFactory;
+    private $streamFactory;
+
+    public function __construct(HttpClientInterface $client, ResponseFactoryInterface $responseFactory, StreamFactoryInterface $streamFactory)
+    {
+        $this->client = $client;
+        $this->responseFactory = $responseFactory;
+        $this->streamFactory = $streamFactory;
+    }
+
+    public function sendRequest(RequestInterface $request): ResponseInterface
+    {
+        try {
+            $response = $this->client->request($request->getMethod(), (string) $request->getUri(), [
+                'headers' => $request->getHeaders(),
+                'body' => (string) $request->getBody(),
+                'http_version' => '1.0' === $request->getProtocolVersion() ? '1.0' : null,
+            ]);
+
+            $psrResponse = $this->responseFactory->createResponse($response->getStatusCode());
+
+            foreach ($response->getHeaders() as $name => $values) {
+                foreach ($values as $value) {
+                    $psrResponse = $psrResponse->withAddedHeader($name, $value);
+                }
+            }
+
+            return $psrResponse->withBody($this->streamFactory->createStream($response->getContent()));
+        } catch (TransportExceptionInterface $e) {
+            if ($e instanceof \InvalidArgumentException) {
+                throw new Psr18RequestException($e, $request);
+            }
+
+            throw new Psr18NetworkException($e, $request);
+        }
+    }
+}
+
+/**
+ * @internal
+ */
+trait Psr18ExceptionTrait
+{
+    private $request;
+
+    public function __construct(TransportExceptionInterface $e, RequestInterface $request)
+    {
+        parent::__construct($e->getMessage(), 0, $e);
+        $this->request = $request;
+    }
+
+    public function getRequest(): RequestInterface
+    {
+        return $this->request;
+    }
+}
+
+/**
+ * @internal
+ */
+class Psr18NetworkException extends \RuntimeException implements NetworkExceptionInterface
+{
+    use Psr18ExceptionTrait;
+}
+
+/**
+ * @internal
+ */
+class Psr18RequestException extends \InvalidArgumentException implements RequestExceptionInterface
+{
+    use Psr18ExceptionTrait;
+}
diff --git a/src/Symfony/Component/HttpClient/README.md b/src/Symfony/Component/HttpClient/README.md
new file mode 100644
index 0000000000..55a0c78ebd
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/README.md
@@ -0,0 +1,17 @@
+HttpClient component
+====================
+
+The HttpClient component provides powerful methods to fetch HTTP resources synchronously or asynchronously.
+
+**This Component is experimental**. [Experimental
+features](https://symfony.com/doc/current/contributing/code/experimental.html)
+are not covered by Symfony's BC-break policy.
+
+Resources
+---------
+
+  * [Documentation](https://symfony.com/doc/current/components/http_client.html)
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)
diff --git a/src/Symfony/Component/HttpClient/Response/CurlResponse.php b/src/Symfony/Component/HttpClient/Response/CurlResponse.php
new file mode 100644
index 0000000000..dadd841d8e
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Response/CurlResponse.php
@@ -0,0 +1,298 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Response;
+
+use Symfony\Component\HttpClient\Chunk\FirstChunk;
+use Symfony\Component\HttpClient\Exception\TransportException;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class CurlResponse implements ResponseInterface
+{
+    use ResponseTrait;
+
+    private static $performing = false;
+
+    /**
+     * @internal
+     */
+    public function __construct(\stdClass $multi, $ch, array $options = null, callable $resolveRedirect = null)
+    {
+        $this->multi = $multi;
+
+        if (\is_resource($ch)) {
+            $this->handle = $ch;
+        } else {
+            $this->info['url'] = $ch;
+            $ch = $this->handle;
+        }
+
+        $this->id = $id = (int) $ch;
+        $this->timeout = $options['timeout'] ?? null;
+        $this->info['user_data'] = $options['user_data'] ?? null;
+        $this->info['start_time'] = $this->info['start_time'] ?? microtime(true);
+        $info = &$this->info;
+
+        if (!$info['raw_headers']) {
+            // Used to keep track of what we're waiting for
+            curl_setopt($ch, CURLOPT_PRIVATE, 'headers');
+        }
+
+        if (null === $content = &$this->content) {
+            $content = ($options['buffer'] ?? true) ? fopen('php://temp', 'w+') : null;
+        } else {
+            // Move the pushed response to the activity list
+            if (ftell($content)) {
+                rewind($content);
+                $multi->handlesActivity[$id][] = stream_get_contents($content);
+            }
+            $content = ($options['buffer'] ?? true) ? $content : null;
+        }
+
+        curl_setopt($ch, CURLOPT_HEADERFUNCTION, static function ($ch, string $data) use (&$info, $options, $multi, $id, &$location, $resolveRedirect): int {
+            return self::parseHeaderLine($ch, $data, $info, $options, $multi, $id, $location, $resolveRedirect);
+        });
+
+        if (null === $options) {
+            // Pushed response: buffer until requested
+            curl_setopt($ch, CURLOPT_WRITEFUNCTION, static function ($ch, string $data) use (&$content): int {
+                return fwrite($content, $data);
+            });
+
+            return;
+        }
+
+        if ($onProgress = $options['on_progress']) {
+            $url = isset($info['url']) ? ['url' => $info['url']] : [];
+            curl_setopt($ch, CURLOPT_NOPROGRESS, false);
+            curl_setopt($ch, CURLOPT_PROGRESSFUNCTION, static function ($ch, $dlSize, $dlNow) use ($onProgress, &$info, $url) {
+                try {
+                    $onProgress($dlNow, $dlSize, $url + curl_getinfo($ch) + $info);
+                } catch (\Throwable $e) {
+                    $info['error'] = $e;
+
+                    return 1; // Abort the request
+                }
+            });
+        }
+
+        curl_setopt($ch, CURLOPT_WRITEFUNCTION, static function ($ch, string $data) use (&$content, $multi, $id): int {
+            $multi->handlesActivity[$id][] = $data;
+
+            return null !== $content ? fwrite($content, $data) : \strlen($data);
+        });
+
+        $this->initializer = static function (self $response) {
+            if (null !== $response->info['error']) {
+                throw new TransportException($response->info['error']);
+            }
+
+            if (\in_array(curl_getinfo($ch = $response->handle, CURLINFO_PRIVATE), ['headers', 'destruct'], true)) {
+                try {
+                    if (\defined('CURLOPT_STREAM_WEIGHT')) {
+                        curl_setopt($ch, CURLOPT_STREAM_WEIGHT, 32);
+                    }
+                    self::stream([$response])->current();
+                } catch (\Throwable $e) {
+                    $response->info['error'] = $e->getMessage();
+                    $response->close();
+                    throw $e;
+                }
+            }
+
+            curl_setopt($ch, CURLOPT_HEADERFUNCTION, null);
+            curl_setopt($ch, CURLOPT_READFUNCTION, null);
+            curl_setopt($ch, CURLOPT_INFILE, null);
+
+            $response->addRawHeaders($response->info['raw_headers']);
+        };
+
+        // Schedule the request in a non-blocking way
+        $multi->openHandles[$id] = $ch;
+        curl_multi_add_handle($multi->handle, $ch);
+        self::perform($multi);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getInfo(string $type = null)
+    {
+        if (!$info = $this->finalInfo) {
+            self::perform($this->multi);
+            $info = array_merge($this->info, curl_getinfo($this->handle));
+            $info['url'] = $this->info['url'] ?? $info['url'];
+            $info['redirect_url'] = $this->info['redirect_url'] ?? null;
+
+            // workaround curl not subtracting the time offset for pushed responses
+            if (isset($this->info['url']) && $info['start_time'] / 1000 < $info['total_time']) {
+                $info['total_time'] -= $info['starttransfer_time'] ?: $info['total_time'];
+                $info['starttransfer_time'] = 0.0;
+            }
+
+            if (!\in_array(curl_getinfo($this->handle, CURLINFO_PRIVATE), ['headers', 'content'], true)) {
+                $this->finalInfo = $info;
+            }
+        }
+
+        return null !== $type ? $info[$type] ?? null : $info;
+    }
+
+    public function __destruct()
+    {
+        try {
+            if (null === $this->timeout || isset($this->info['url'])) {
+                return; // pushed response
+            }
+
+            if ('content' === $waitFor = curl_getinfo($this->handle, CURLINFO_PRIVATE)) {
+                $this->close();
+            } elseif ('headers' === $waitFor) {
+                curl_setopt($this->handle, CURLOPT_PRIVATE, 'destruct');
+            }
+
+            $this->doDestruct();
+        } finally {
+            $this->close();
+
+            // Clear local caches when the only remaining handles are about pushed responses
+            if (\count($this->multi->openHandles) === \count($this->multi->pushedResponses)) {
+                $this->multi->pushedResponses = [];
+                // Schedule DNS cache eviction for the next request
+                $this->multi->dnsCache[2] = $this->multi->dnsCache[2] ?: $this->multi->dnsCache[1];
+                $this->multi->dnsCache[1] = $this->multi->dnsCache[0] = [];
+            }
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function close(): void
+    {
+        unset($this->multi->openHandles[$this->id], $this->multi->handlesActivity[$this->id]);
+        curl_multi_remove_handle($this->multi->handle, $this->handle);
+        curl_setopt_array($this->handle, [
+            CURLOPT_PRIVATE => '',
+            CURLOPT_NOPROGRESS => true,
+            CURLOPT_PROGRESSFUNCTION => null,
+            CURLOPT_HEADERFUNCTION => null,
+            CURLOPT_WRITEFUNCTION => null,
+            CURLOPT_READFUNCTION => null,
+            CURLOPT_INFILE => null,
+        ]);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected static function schedule(self $response, array &$runningResponses): void
+    {
+        if ('' === curl_getinfo($ch = $response->handle, CURLINFO_PRIVATE)) {
+            // no-op - response already completed
+        } elseif (isset($runningResponses[$i = (int) $response->multi->handle])) {
+            $runningResponses[$i][1][$response->id] = $response;
+        } else {
+            $runningResponses[$i] = [$response->multi, [$response->id => $response]];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected static function perform(\stdClass $multi, array &$responses = null): void
+    {
+        if (self::$performing) {
+            return;
+        }
+
+        try {
+            self::$performing = true;
+            while (CURLM_CALL_MULTI_PERFORM === curl_multi_exec($multi->handle, $active));
+
+            while ($info = curl_multi_info_read($multi->handle)) {
+                $multi->handlesActivity[(int) $info['handle']][] = null;
+                $multi->handlesActivity[(int) $info['handle']][] = \in_array($info['result'], [\CURLE_OK, \CURLE_TOO_MANY_REDIRECTS], true) ? null : new TransportException(curl_error($info['handle']));
+            }
+        } finally {
+            self::$performing = false;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected static function select(\stdClass $multi, float $timeout): int
+    {
+        return curl_multi_select($multi->handle, $timeout);
+    }
+
+    /**
+     * Parses header lines as curl yields them to us.
+     */
+    private static function parseHeaderLine($ch, string $data, array &$info, ?array $options, \stdClass $multi, int $id, ?string &$location, ?callable $resolveRedirect): int
+    {
+        if (!\in_array($waitFor = @curl_getinfo($ch, CURLINFO_PRIVATE), ['headers', 'destruct'], true)) {
+            return \strlen($data); // Ignore HTTP trailers
+        }
+
+        if ("\r\n" !== $data) {
+            // Regular header line: add it to the list
+            $info['raw_headers'][] = substr($data, 0, -2);
+
+            if (0 === stripos($data, 'Location:')) {
+                $location = trim(substr($data, 9, -2));
+            }
+
+            return \strlen($data);
+        }
+
+        // End of headers: handle redirects and add to the activity list
+        $statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
+        $info['redirect_url'] = null;
+
+        if (300 <= $statusCode && $statusCode < 400 && null !== $location) {
+            $info['redirect_url'] = $resolveRedirect($ch, $location);
+            $url = parse_url($location ?? ':');
+
+            if (isset($url['host']) && null !== $ip = $multi->dnsCache[0][$url['host'] = strtolower($url['host'])] ?? null) {
+                // Populate DNS cache for redirects if needed
+                $port = $url['port'] ?? ('http' === ($url['scheme'] ?? parse_url(curl_getinfo($ch, CURLINFO_EFFECTIVE_URL), PHP_URL_SCHEME)) ? 80 : 443);
+                curl_setopt($ch, CURLOPT_RESOLVE, ["{$url['host']}:$port:$ip"]);
+                $multi->dnsCache[1]["-{$url['host']}:$port"] = "-{$url['host']}:$port";
+            }
+        }
+
+        $location = null;
+
+        if ($statusCode < 300 || 400 <= $statusCode || curl_getinfo($ch, CURLINFO_REDIRECT_COUNT) === $options['max_redirects']) {
+            // Headers and redirects completed, time to get the response's body
+            $multi->handlesActivity[$id] = [new FirstChunk()];
+
+            if ('destruct' === $waitFor) {
+                return 0;
+            }
+
+            if ($certinfo = curl_getinfo($ch, CURLINFO_CERTINFO)) {
+                $info['peer_certificate_chain'] = array_map('openssl_x509_read', array_column($certinfo, 'Cert'));
+            }
+
+            curl_setopt($ch, CURLOPT_PRIVATE, 'content');
+        }
+
+        return \strlen($data);
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Response/NativeResponse.php b/src/Symfony/Component/HttpClient/Response/NativeResponse.php
new file mode 100644
index 0000000000..3e9ee3a375
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Response/NativeResponse.php
@@ -0,0 +1,305 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Response;
+
+use Symfony\Component\HttpClient\Chunk\FirstChunk;
+use Symfony\Component\HttpClient\Exception\TransportException;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class NativeResponse implements ResponseInterface
+{
+    use ResponseTrait;
+
+    private $context;
+    private $url;
+    private $resolveRedirect;
+    private $onProgress;
+    private $remaining;
+    private $buffer;
+    private $inflate;
+
+    /**
+     * @internal
+     */
+    public function __construct(\stdClass $multi, $context, string $url, $options, bool $gzipEnabled, array &$info, callable $resolveRedirect, ?callable $onProgress)
+    {
+        $this->multi = $multi;
+        $this->id = (int) $context;
+        $this->context = $context;
+        $this->url = $url;
+        $this->timeout = $options['timeout'];
+        $this->info = &$info;
+        $this->resolveRedirect = $resolveRedirect;
+        $this->onProgress = $onProgress;
+        $this->content = $options['buffer'] ? fopen('php://temp', 'w+') : null;
+
+        // Temporary resources to dechunk/inflate the response stream
+        $this->buffer = fopen('php://temp', 'w+');
+        $this->inflate = $gzipEnabled ? inflate_init(ZLIB_ENCODING_GZIP) : null;
+
+        $info['user_data'] = $options['user_data'];
+        ++$multi->responseCount;
+
+        $this->initializer = static function (self $response) {
+            if (null !== $response->info['error']) {
+                throw new TransportException($response->info['error']);
+            }
+
+            if (null === $response->remaining) {
+                self::stream([$response])->current();
+            }
+        };
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getInfo(string $type = null)
+    {
+        if (!$info = $this->finalInfo) {
+            self::perform($this->multi);
+            $info = $this->info;
+            $info['url'] = implode('', $info['url']);
+            unset($info['fopen_time'], $info['size_body']);
+
+            if (null === $this->buffer) {
+                $this->finalInfo = $info;
+            }
+        }
+
+        return null !== $type ? $info[$type] ?? null : $info;
+    }
+
+    public function __destruct()
+    {
+        try {
+            $this->doDestruct();
+        } finally {
+            $this->close();
+
+            // Clear the DNS cache when all requests completed
+            if (0 >= --$this->multi->responseCount) {
+                $this->multi->responseCount = 0;
+                $this->multi->dnsCache = [];
+            }
+        }
+    }
+
+    private function open(): void
+    {
+        set_error_handler(function ($type, $msg) { throw new TransportException($msg); });
+
+        try {
+            $this->info['start_time'] = microtime(true);
+            $url = $this->url;
+
+            do {
+                // Send request and follow redirects when needed
+                $this->info['fopen_time'] = microtime(true);
+                $this->handle = $h = fopen($url, 'r', false, $this->context);
+                $this->addRawHeaders($http_response_header);
+                $url = ($this->resolveRedirect)($this->multi, $this->statusCode, $this->headers['location'][0] ?? null, $this->context);
+            } while (null !== $url);
+        } catch (\Throwable $e) {
+            $this->statusCode = 0;
+            $this->close();
+            $this->multi->handlesActivity[$this->id][] = null;
+            $this->multi->handlesActivity[$this->id][] = $e;
+
+            return;
+        } finally {
+            $this->info['starttransfer_time'] = $this->info['total_time'] = microtime(true) - $this->info['start_time'];
+            restore_error_handler();
+        }
+
+        stream_set_blocking($h, false);
+        $context = stream_context_get_options($this->context);
+        $this->context = $this->resolveRedirect = null;
+
+        if (isset($context['ssl']['peer_certificate_chain'])) {
+            $this->info['peer_certificate_chain'] = $context['ssl']['peer_certificate_chain'];
+        }
+
+        // Create dechunk and inflate buffers
+        if (isset($this->headers['content-length'])) {
+            $this->remaining = (int) $this->headers['content-length'][0];
+        } elseif ('chunked' === ($this->headers['transfer-encoding'][0] ?? null)) {
+            stream_filter_append($this->buffer, 'dechunk', STREAM_FILTER_WRITE);
+            $this->remaining = -1;
+        } else {
+            $this->remaining = -2;
+        }
+
+        if ($this->inflate && 'gzip' !== ($this->headers['content-encoding'][0] ?? null)) {
+            $this->inflate = null;
+        }
+
+        $this->multi->openHandles[$this->id] = [$h, $this->buffer, $this->inflate, &$this->content, $this->onProgress, &$this->remaining, &$this->info];
+        $this->multi->handlesActivity[$this->id] = [new FirstChunk()];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    private function close(): void
+    {
+        unset($this->multi->openHandles[$this->id], $this->multi->handlesActivity[$this->id]);
+        $this->handle = $this->buffer = $this->inflate = $this->onProgress = null;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    private static function schedule(self $response, array &$runningResponses): void
+    {
+        if (null === $response->buffer) {
+            return;
+        }
+
+        if (!isset($runningResponses[$i = $response->multi->id])) {
+            $runningResponses[$i] = [$response->multi, []];
+        }
+
+        if (null === $response->remaining) {
+            $response->multi->pendingResponses[] = $response;
+        } else {
+            $runningResponses[$i][1][$response->id] = $response;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    private static function perform(\stdClass $multi, array &$responses = null): void
+    {
+        // List of native handles for stream_select()
+        if (null !== $responses) {
+            $multi->handles = [];
+        }
+
+        foreach ($multi->openHandles as $i => [$h, $buffer, $inflate, $content, $onProgress]) {
+            $hasActivity = false;
+            $remaining = &$multi->openHandles[$i][5];
+            $info = &$multi->openHandles[$i][6];
+            $e = null;
+
+            // Read incoming buffer and write it to the dechunk one
+            try {
+                while ($remaining && '' !== $data = (string) fread($h, 0 > $remaining ? 16372 : $remaining)) {
+                    fwrite($buffer, $data);
+                    $hasActivity = true;
+                    $multi->sleep = false;
+
+                    if (-1 !== $remaining) {
+                        $remaining -= \strlen($data);
+                    }
+                }
+            } catch (\Throwable $e) {
+                $hasActivity = $onProgress = false;
+            }
+
+            if (!$hasActivity) {
+                if ($onProgress) {
+                    try {
+                        // Notify the progress callback so that it can e.g. cancel
+                        // the request if the stream is inactive for too long
+                        $onProgress();
+                    } catch (\Throwable $e) {
+                        // no-op
+                    }
+                }
+            } elseif ('' !== $data = stream_get_contents($buffer, -1, 0)) {
+                rewind($buffer);
+                ftruncate($buffer, 0);
+
+                if (null !== $inflate && false === $data = @inflate_add($inflate, $data)) {
+                    $e = new TransportException('Error while processing content unencoding.');
+                }
+
+                if ('' !== $data && null === $e) {
+                    $multi->handlesActivity[$i][] = $data;
+
+                    if (null !== $content && \strlen($data) !== fwrite($content, $data)) {
+                        $e = new TransportException(sprintf('Failed writing %d bytes to the response buffer.', \strlen($data)));
+                    }
+                }
+            }
+
+            if (null !== $e || !$remaining || feof($h)) {
+                // Stream completed
+                $info['total_time'] = microtime(true) - $info['start_time'];
+
+                if ($onProgress) {
+                    try {
+                        $onProgress(-1);
+                    } catch (\Throwable $e) {
+                        // no-op
+                    }
+                }
+
+                if (null === $e) {
+                    if (0 < $remaining) {
+                        $e = new TransportException(sprintf('Transfer closed with %s bytes remaining to read.', $remaining));
+                    } elseif (-1 === $remaining && fwrite($buffer, '-') && '' !== stream_get_contents($buffer, -1, 0)) {
+                        $e = new TransportException('Transfer closed with outstanding data remaining from chunked response.');
+                    }
+                }
+
+                $multi->handlesActivity[$i][] = null;
+                $multi->handlesActivity[$i][] = $e;
+                unset($multi->openHandles[$i]);
+                $multi->sleep = false;
+            } elseif (null !== $responses) {
+                $multi->handles[] = $h;
+            }
+        }
+
+        if (null === $responses) {
+            return;
+        }
+
+        if ($multi->pendingResponses && \count($multi->handles) < $multi->maxHostConnections) {
+            // Open the next pending request - this is a blocking operation so we do only one of them
+            $response = array_shift($multi->pendingResponses);
+            $response->open();
+            $responses[$response->id] = $response;
+            $multi->sleep = false;
+            self::perform($response->multi);
+
+            if (null !== $response->handle) {
+                $multi->handles[] = $response->handle;
+            }
+        }
+
+        if ($multi->pendingResponses) {
+            // Create empty activity list to tell ResponseTrait::stream() we still have pending requests
+            $response = $multi->pendingResponses[0];
+            $responses[$response->id] = $response;
+            $multi->handlesActivity[$response->id] = [];
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    private static function select(\stdClass $multi, float $timeout): int
+    {
+        $_ = [];
+
+        return (!$multi->sleep = !$multi->sleep) ? -1 : stream_select($multi->handles, $_, $_, (int) $timeout, (int) (1E6 * ($timeout - (int) $timeout)));
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Response/ResponseStream.php b/src/Symfony/Component/HttpClient/Response/ResponseStream.php
new file mode 100644
index 0000000000..cf53abcded
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Response/ResponseStream.php
@@ -0,0 +1,56 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Response;
+
+use Symfony\Contracts\HttpClient\ChunkInterface;
+use Symfony\Contracts\HttpClient\ResponseInterface;
+use Symfony\Contracts\HttpClient\ResponseStreamInterface;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+final class ResponseStream implements ResponseStreamInterface
+{
+    private $generator;
+
+    public function __construct(\Generator $generator)
+    {
+        $this->generator = $generator;
+    }
+
+    public function key(): ResponseInterface
+    {
+        return $this->generator->key();
+    }
+
+    public function current(): ChunkInterface
+    {
+        return $this->generator->current();
+    }
+
+    public function next(): void
+    {
+        $this->generator->next();
+    }
+
+    public function rewind(): void
+    {
+        $this->generator->rewind();
+    }
+
+    public function valid(): bool
+    {
+        return $this->generator->valid();
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Response/ResponseTrait.php b/src/Symfony/Component/HttpClient/Response/ResponseTrait.php
new file mode 100644
index 0000000000..b31af23d4c
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Response/ResponseTrait.php
@@ -0,0 +1,299 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Response;
+
+use Symfony\Component\HttpClient\Chunk\DataChunk;
+use Symfony\Component\HttpClient\Chunk\ErrorChunk;
+use Symfony\Component\HttpClient\Chunk\LastChunk;
+use Symfony\Component\HttpClient\Exception\ClientException;
+use Symfony\Component\HttpClient\Exception\RedirectionException;
+use Symfony\Component\HttpClient\Exception\ServerException;
+use Symfony\Component\HttpClient\Exception\TransportException;
+
+/**
+ * Implements the common logic for response classes.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @internal
+ */
+trait ResponseTrait
+{
+    private $statusCode = 0;
+    private $headers = [];
+
+    /**
+     * @var callable|null A callback that initializes the two previous properties
+     */
+    private $initializer;
+
+    /**
+     * @var resource A php://temp stream typically
+     */
+    private $content;
+
+    private $info = [
+        'raw_headers' => [],
+        'error' => null,
+    ];
+
+    private $multi;
+    private $handle;
+    private $id;
+    private $timeout;
+    private $finalInfo;
+    private $offset = 0;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getStatusCode(): int
+    {
+        if ($this->initializer) {
+            ($this->initializer)($this);
+            $this->initializer = null;
+        }
+
+        return $this->statusCode;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getHeaders(bool $throw = true): array
+    {
+        if ($this->initializer) {
+            ($this->initializer)($this);
+            $this->initializer = null;
+        }
+
+        if ($throw) {
+            $this->checkStatusCode();
+        }
+
+        return $this->headers;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContent(bool $throw = true): string
+    {
+        if ($this->initializer) {
+            ($this->initializer)($this);
+            $this->initializer = null;
+        }
+
+        if ($throw) {
+            $this->checkStatusCode();
+        }
+
+        if (null === $this->content) {
+            $content = '';
+            $chunk = null;
+
+            foreach (self::stream([$this]) as $chunk) {
+                $content .= $chunk->getContent();
+            }
+
+            if (null === $chunk) {
+                throw new TransportException('Cannot get the content of the response twice: the request was issued with option "buffer" set to false.');
+            }
+
+            return $content;
+        }
+
+        foreach (self::stream([$this]) as $chunk) {
+            // Chunks are buffered in $this->content already
+        }
+
+        rewind($this->content);
+
+        return stream_get_contents($this->content);
+    }
+
+    /**
+     * Closes the response and all its network handles.
+     */
+    abstract protected function close(): void;
+
+    /**
+     * Adds pending responses to the activity list.
+     */
+    abstract protected static function schedule(self $response, array &$runningResponses): void;
+
+    /**
+     * Performs all pending non-blocking operations.
+     */
+    abstract protected static function perform(\stdClass $multi, array &$responses): void;
+
+    /**
+     * Waits for network activity.
+     */
+    abstract protected static function select(\stdClass $multi, float $timeout): int;
+
+    private function addRawHeaders(array $rawHeaders): void
+    {
+        foreach ($rawHeaders as $h) {
+            if (11 <= \strlen($h) && '/' === $h[4] && preg_match('#^HTTP/\d+(?:\.\d+)? ([12345]\d\d) .*#', $h, $m)) {
+                $this->headers = [];
+                $this->info['http_code'] = $this->statusCode = (int) $m[1];
+            } elseif (2 === \count($m = explode(':', $h, 2))) {
+                $this->headers[strtolower($m[0])][] = ltrim($m[1]);
+            }
+
+            $this->info['raw_headers'][] = $h;
+        }
+
+        if (!$this->statusCode) {
+            throw new TransportException('Invalid or missing HTTP status line.');
+        }
+    }
+
+    private function checkStatusCode()
+    {
+        if (500 <= $this->statusCode) {
+            throw new ServerException($this);
+        }
+
+        if (400 <= $this->statusCode) {
+            throw new ClientException($this);
+        }
+
+        if (300 <= $this->statusCode) {
+            throw new RedirectionException($this);
+        }
+    }
+
+    /**
+     * Ensures the request is always sent and that the response code was checked.
+     */
+    private function doDestruct()
+    {
+        if ($this->initializer && null === $this->info['error']) {
+            ($this->initializer)($this);
+            $this->initializer = null;
+            $this->checkStatusCode();
+        }
+    }
+
+    /**
+     * Implements an event loop based on a buffer activity queue.
+     *
+     * @internal
+     */
+    public static function stream(iterable $responses, float $timeout = null): \Generator
+    {
+        $runningResponses = [];
+
+        foreach ($responses as $response) {
+            self::schedule($response, $runningResponses);
+        }
+
+        $lastActivity = microtime(true);
+        $isTimeout = false;
+
+        while (true) {
+            $hasActivity = false;
+            $timeoutMax = 0;
+            $timeoutMin = $timeout ?? INF;
+
+            foreach ($runningResponses as $i => [$multi]) {
+                $responses = &$runningResponses[$i][1];
+                self::perform($multi, $responses);
+
+                foreach ($responses as $j => $response) {
+                    $timeoutMax = $timeout ?? max($timeoutMax, $response->timeout);
+                    $timeoutMin = min($timeoutMin, $response->timeout, 1);
+                    // ErrorChunk instances will set $didThrow to true when the
+                    // exception they wrap has been thrown after yielding
+                    $chunk = $didThrow = false;
+
+                    if (isset($multi->handlesActivity[$j])) {
+                        // no-op
+                    } elseif (!isset($multi->openHandles[$j])) {
+                        unset($responses[$j]);
+                        continue;
+                    } elseif ($isTimeout) {
+                        $multi->handlesActivity[$j] = [new ErrorChunk($didThrow, $response->offset)];
+                    } else {
+                        continue;
+                    }
+
+                    while ($multi->handlesActivity[$j] ?? false) {
+                        $hasActivity = true;
+                        $isTimeout = false;
+
+                        if (\is_string($chunk = array_shift($multi->handlesActivity[$j]))) {
+                            $response->offset += \strlen($chunk);
+                            $chunk = new DataChunk($response->offset, $chunk);
+                        } elseif (null === $chunk) {
+                            if (null !== $e = $response->info['error'] ?? $multi->handlesActivity[$j][0]) {
+                                $response->info['error'] = $e->getMessage();
+
+                                if ($e instanceof \Error) {
+                                    unset($responses[$j], $multi->handlesActivity[$j]);
+                                    $response->close();
+                                    throw $e;
+                                }
+
+                                $chunk = new ErrorChunk($didThrow, $response->offset, $e);
+                            } else {
+                                $chunk = new LastChunk($response->offset);
+                            }
+
+                            unset($responses[$j]);
+                            $response->close();
+                        } elseif ($chunk instanceof ErrorChunk) {
+                            unset($responses[$j]);
+                            $isTimeout = true;
+                        }
+
+                        yield $response => $chunk;
+                    }
+
+                    unset($multi->handlesActivity[$j]);
+
+                    if ($chunk instanceof FirstChunk && null === $response->initializer) {
+                        // Ensure the HTTP status code is always checked
+                        $response->getHeaders(true);
+                    } elseif ($chunk instanceof ErrorChunk && !$didThrow) {
+                        // Ensure transport exceptions are always thrown
+                        $chunk->getContent();
+                    }
+                }
+
+                if (!$responses) {
+                    unset($runningResponses[$i]);
+                }
+
+                // Prevent memory leaks
+                $multi->handlesActivity = $multi->handlesActivity ?: [];
+                $multi->openHandles = $multi->openHandles ?: [];
+            }
+
+            if (!$runningResponses) {
+                break;
+            }
+
+            if ($hasActivity) {
+                $lastActivity = microtime(true);
+                continue;
+            }
+
+            switch (self::select($multi, $timeoutMin)) {
+                case -1: usleep(min(500, 1E6 * $timeoutMin)); break;
+                case 0: $isTimeout = microtime(true) - $lastActivity > $timeoutMax; break;
+            }
+        }
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Tests/CurlHttpClientTest.php b/src/Symfony/Component/HttpClient/Tests/CurlHttpClientTest.php
new file mode 100644
index 0000000000..7c51d42236
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Tests/CurlHttpClientTest.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Tests;
+
+use Symfony\Component\HttpClient\CurlHttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\Test\HttpClientTestCase;
+
+/**
+ * @requires extension curl
+ */
+class CurlHttpClientTest extends HttpClientTestCase
+{
+    protected function getHttpClient(): HttpClientInterface
+    {
+        return new CurlHttpClient();
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Tests/HttpClientTest.php b/src/Symfony/Component/HttpClient/Tests/HttpClientTest.php
new file mode 100644
index 0000000000..9f70b74396
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Tests/HttpClientTest.php
@@ -0,0 +1,29 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpClient\CurlHttpClient;
+use Symfony\Component\HttpClient\HttpClient;
+use Symfony\Component\HttpClient\NativeHttpClient;
+
+class HttpClientTest extends TestCase
+{
+    public function testCreateClient()
+    {
+        if (\extension_loaded('curl')) {
+            $this->assertInstanceOf(CurlHttpClient::class, HttpClient::create());
+        } else {
+            $this->assertInstanceOf(NativeHttpClient::class, HttpClient::create());
+        }
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php b/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php
new file mode 100644
index 0000000000..815a1ab617
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php
@@ -0,0 +1,166 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpClient\HttpClientTrait;
+
+class HttpClientTraitTest extends TestCase
+{
+    use HttpClientTrait;
+
+    private const RFC3986_BASE = 'http://a/b/c/d;p?q';
+
+    /**
+     * @dataProvider providePrepareRequestUrl
+     */
+    public function testPrepareRequestUrl($expected, $url, $query = [])
+    {
+        $defaults = [
+            'base_uri' => 'http://example.com?c=c',
+            'query' => ['a' => 1, 'b' => 'b'],
+        ];
+        [, $defaults] = self::prepareRequest(null, null, $defaults);
+
+        [$url] = self::prepareRequest(null, $url, ['query' => $query], $defaults);
+        $this->assertSame($expected, implode('', $url));
+    }
+
+    public function providePrepareRequestUrl()
+    {
+        yield ['http://example.com/', 'http://example.com/'];
+        yield ['http://example.com/?a=1&b=b', '.'];
+        yield ['http://example.com/?a=2&b=b', '.?a=2'];
+        yield ['http://example.com/?a=3&b=b', '.', ['a' => 3]];
+        yield ['http://example.com/?a=3&b=b', '.?a=0', ['a' => 3]];
+    }
+
+    /**
+     * @dataProvider provideResolveUrl
+     */
+    public function testResolveUrl($base, $url, $expected)
+    {
+        $this->assertSame($expected, implode('', self::resolveUrl(self::parseUrl($url), self::parseUrl($base))));
+    }
+
+    /**
+     * From https://github.com/guzzle/psr7/blob/master/tests/UriResoverTest.php.
+     */
+    public function provideResolveUrl()
+    {
+        return [
+            [self::RFC3986_BASE, 'http:h',        'http:h'],
+            [self::RFC3986_BASE, 'g',             'http://a/b/c/g'],
+            [self::RFC3986_BASE, './g',           'http://a/b/c/g'],
+            [self::RFC3986_BASE, 'g/',            'http://a/b/c/g/'],
+            [self::RFC3986_BASE, '/g',            'http://a/g'],
+            [self::RFC3986_BASE, '//g',           'http://g/'],
+            [self::RFC3986_BASE, '?y',            'http://a/b/c/d;p?y'],
+            [self::RFC3986_BASE, 'g?y',           'http://a/b/c/g?y'],
+            [self::RFC3986_BASE, '#s',            'http://a/b/c/d;p?q#s'],
+            [self::RFC3986_BASE, 'g#s',           'http://a/b/c/g#s'],
+            [self::RFC3986_BASE, 'g?y#s',         'http://a/b/c/g?y#s'],
+            [self::RFC3986_BASE, ';x',            'http://a/b/c/;x'],
+            [self::RFC3986_BASE, 'g;x',           'http://a/b/c/g;x'],
+            [self::RFC3986_BASE, 'g;x?y#s',       'http://a/b/c/g;x?y#s'],
+            [self::RFC3986_BASE, '',              self::RFC3986_BASE],
+            [self::RFC3986_BASE, '.',             'http://a/b/c/'],
+            [self::RFC3986_BASE, './',            'http://a/b/c/'],
+            [self::RFC3986_BASE, '..',            'http://a/b/'],
+            [self::RFC3986_BASE, '../',           'http://a/b/'],
+            [self::RFC3986_BASE, '../g',          'http://a/b/g'],
+            [self::RFC3986_BASE, '../..',         'http://a/'],
+            [self::RFC3986_BASE, '../../',        'http://a/'],
+            [self::RFC3986_BASE, '../../g',       'http://a/g'],
+            [self::RFC3986_BASE, '../../../g',    'http://a/g'],
+            [self::RFC3986_BASE, '../../../../g', 'http://a/g'],
+            [self::RFC3986_BASE, '/./g',          'http://a/g'],
+            [self::RFC3986_BASE, '/../g',         'http://a/g'],
+            [self::RFC3986_BASE, 'g.',            'http://a/b/c/g.'],
+            [self::RFC3986_BASE, '.g',            'http://a/b/c/.g'],
+            [self::RFC3986_BASE, 'g..',           'http://a/b/c/g..'],
+            [self::RFC3986_BASE, '..g',           'http://a/b/c/..g'],
+            [self::RFC3986_BASE, './../g',        'http://a/b/g'],
+            [self::RFC3986_BASE, 'foo////g',      'http://a/b/c/foo////g'],
+            [self::RFC3986_BASE, './g/.',         'http://a/b/c/g/'],
+            [self::RFC3986_BASE, 'g/./h',         'http://a/b/c/g/h'],
+            [self::RFC3986_BASE, 'g/../h',        'http://a/b/c/h'],
+            [self::RFC3986_BASE, 'g;x=1/./y',     'http://a/b/c/g;x=1/y'],
+            [self::RFC3986_BASE, 'g;x=1/../y',    'http://a/b/c/y'],
+            // dot-segments in the query or fragment
+            [self::RFC3986_BASE, 'g?y/./x',       'http://a/b/c/g?y/./x'],
+            [self::RFC3986_BASE, 'g?y/../x',      'http://a/b/c/g?y/../x'],
+            [self::RFC3986_BASE, 'g#s/./x',       'http://a/b/c/g#s/./x'],
+            [self::RFC3986_BASE, 'g#s/../x',      'http://a/b/c/g#s/../x'],
+            [self::RFC3986_BASE, 'g#s/../x',      'http://a/b/c/g#s/../x'],
+            [self::RFC3986_BASE, '?y#s',          'http://a/b/c/d;p?y#s'],
+            // base with fragment
+            ['http://a/b/c?q#s', '?y',            'http://a/b/c?y'],
+            // base with user info
+            ['http://u@a/b/c/d;p?q', '.',         'http://u@a/b/c/'],
+            ['http://u:p@a/b/c/d;p?q', '.',       'http://u:p@a/b/c/'],
+            // path ending with slash or no slash at all
+            ['http://a/b/c/d/',  'e',             'http://a/b/c/d/e'],
+            ['http:no-slash',     'e',            'http:e'],
+            // falsey relative parts
+            [self::RFC3986_BASE, '//0',           'http://0/'],
+            [self::RFC3986_BASE, '0',             'http://a/b/c/0'],
+            [self::RFC3986_BASE, '?0',            'http://a/b/c/d;p?0'],
+            [self::RFC3986_BASE, '#0',            'http://a/b/c/d;p?q#0'],
+        ];
+    }
+
+    /**
+     * @dataProvider provideParseUrl
+     */
+    public function testParseUrl($expected, $url, $query = [])
+    {
+        $expected = array_combine(['scheme', 'authority', 'path', 'query', 'fragment'], $expected);
+
+        $this->assertSame($expected, self::parseUrl($url, $query));
+    }
+
+    public function provideParseUrl()
+    {
+        yield [['http:', '//example.com', null, null, null], 'http://Example.coM:80'];
+        yield [['https:', '//xn--dj-kia8a.example.com:8000', '/', null, null], 'https://DÉjà.Example.com:8000/'];
+        yield [[null, null, '/f%20o.o', '?a=b', '#c'], '/f o%2Eo?a=b#c'];
+        yield [[null, '//a:b@foo', '/bar', null, null], '//a:b@foo/bar'];
+        yield [['http:', null, null, null, null], 'http:'];
+        yield [['http:', null, 'bar', null, null], 'http:bar'];
+        yield [[null, null, 'bar', '?a=1&c=c', null], 'bar?a=a&b=b', ['b' => null, 'c' => 'c', 'a' => 1]];
+        yield [[null, null, 'bar', '?a=b+c&b=b', null], 'bar?a=b+c', ['b' => 'b']];
+        yield [[null, null, 'bar', '?a=b%2B%20c', null], 'bar?a=b+c', ['a' => 'b+ c']];
+    }
+
+    /**
+     * @dataProvider provideRemoveDotSegments
+     */
+    public function testRemoveDotSegments($expected, $url)
+    {
+        $this->assertSame($expected, self::removeDotSegments($url));
+    }
+
+    public function provideRemoveDotSegments()
+    {
+        yield ['', ''];
+        yield ['', '.'];
+        yield ['', '..'];
+        yield ['a', './a'];
+        yield ['a', '../a'];
+        yield ['/a/b', '/a/./b'];
+        yield ['/b/', '/a/../b/.'];
+        yield ['/a//b/', '/a///../b/.'];
+        yield ['/a/', '/a/b/..'];
+        yield ['/a///b', '/a///b'];
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Tests/NativeHttpClientTest.php b/src/Symfony/Component/HttpClient/Tests/NativeHttpClientTest.php
new file mode 100644
index 0000000000..d2af0584f9
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Tests/NativeHttpClientTest.php
@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Tests;
+
+use Symfony\Component\HttpClient\NativeHttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Symfony\Contracts\HttpClient\Test\HttpClientTestCase;
+
+class NativeHttpClientTest extends HttpClientTestCase
+{
+    protected function getHttpClient(): HttpClientInterface
+    {
+        return new NativeHttpClient();
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/Tests/Psr18ClientTest.php b/src/Symfony/Component/HttpClient/Tests/Psr18ClientTest.php
new file mode 100644
index 0000000000..edb2891a37
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/Tests/Psr18ClientTest.php
@@ -0,0 +1,77 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpClient\Tests;
+
+use Nyholm\Psr7\Factory\Psr17Factory;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpClient\NativeHttpClient;
+use Symfony\Component\HttpClient\Psr18Client;
+use Symfony\Component\HttpClient\Psr18NetworkException;
+use Symfony\Component\HttpClient\Psr18RequestException;
+use Symfony\Contracts\HttpClient\Test\TestHttpServer;
+
+class Psr18ClientTest extends TestCase
+{
+    private static $server;
+
+    public static function setUpBeforeClass()
+    {
+        TestHttpServer::start();
+    }
+
+    public function testSendRequest()
+    {
+        $factory = new Psr17Factory();
+        $client = new Psr18Client(new NativeHttpClient(), $factory, $factory);
+
+        $response = $client->sendRequest($factory->createRequest('GET', 'http://localhost:8057'));
+
+        $this->assertSame(200, $response->getStatusCode());
+        $this->assertSame('application/json', $response->getHeaderLine('content-type'));
+
+        $body = json_decode((string) $response->getBody(), true);
+
+        $this->assertSame('HTTP/1.1', $body['SERVER_PROTOCOL']);
+    }
+
+    public function testPostRequest()
+    {
+        $factory = new Psr17Factory();
+        $client = new Psr18Client(new NativeHttpClient(), $factory, $factory);
+
+        $request = $factory->createRequest('POST', 'http://localhost:8057/post')
+            ->withBody($factory->createStream('foo=0123456789'));
+
+        $response = $client->sendRequest($request);
+        $body = json_decode((string) $response->getBody(), true);
+
+        $this->assertSame(['foo' => '0123456789', 'REQUEST_METHOD' => 'POST'], $body);
+    }
+
+    public function testNetworkException()
+    {
+        $factory = new Psr17Factory();
+        $client = new Psr18Client(new NativeHttpClient(), $factory, $factory);
+
+        $this->expectException(Psr18NetworkException::class);
+        $client->sendRequest($factory->createRequest('GET', 'http://localhost:8058'));
+    }
+
+    public function testRequestException()
+    {
+        $factory = new Psr17Factory();
+        $client = new Psr18Client(new NativeHttpClient(), $factory, $factory);
+
+        $this->expectException(Psr18RequestException::class);
+        $client->sendRequest($factory->createRequest('BAD.METHOD', 'http://localhost:8057'));
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/composer.json b/src/Symfony/Component/HttpClient/composer.json
new file mode 100644
index 0000000000..854c2c64fe
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/composer.json
@@ -0,0 +1,42 @@
+{
+    "name": "symfony/http-client",
+    "type": "library",
+    "description": "Symfony HttpClient component",
+    "homepage": "https://symfony.com",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Nicolas Grekas",
+            "email": "p@tchwork.com"
+        },
+        {
+            "name": "Symfony Community",
+            "homepage": "https://symfony.com/contributors"
+        }
+    ],
+    "provide": {
+        "psr/http-client-implementation": "1.0",
+        "symfony/http-client-contracts-implementation": "1.1"
+    },
+    "require": {
+        "php": "^7.1.3",
+        "symfony/contracts": "^1.1"
+    },
+    "require-dev": {
+        "nyholm/psr7": "^1.0",
+        "psr/http-client": "^1.0",
+        "symfony/process": "~4.2"
+    },
+    "autoload": {
+        "psr-4": { "Symfony\\Component\\HttpClient\\": "" },
+        "exclude-from-classmap": [
+            "/Tests/"
+        ]
+    },
+    "minimum-stability": "dev",
+    "extra": {
+        "branch-alias": {
+            "dev-master": "4.3-dev"
+        }
+    }
+}
diff --git a/src/Symfony/Component/HttpClient/phpunit.xml.dist b/src/Symfony/Component/HttpClient/phpunit.xml.dist
new file mode 100644
index 0000000000..4a055dcf50
--- /dev/null
+++ b/src/Symfony/Component/HttpClient/phpunit.xml.dist
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.2/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Symfony HttpClient Component Test Suite">
+            <directory>./Tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./</directory>
+            <exclude>
+                <directory>./Tests</directory>
+                <directory>./vendor</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php b/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
index ae7134f55b..78acb90b66 100644
--- a/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
@@ -40,4 +40,12 @@ class SymfonyCaster
 
         return $a;
     }
+
+    public static function castHttpClient($client, array $a, Stub $stub, $isNested)
+    {
+        $multiKey = sprintf("\0%s\0multi", \get_class($client));
+        $a[$multiKey] = new CutStub($a[$multiKey]);
+
+        return $a;
+    }
 }
diff --git a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
index 9836040e34..e2393c4dbe 100644
--- a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
+++ b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
@@ -75,6 +75,10 @@ abstract class AbstractCloner implements ClonerInterface
         'Exception' => ['Symfony\Component\VarDumper\Caster\ExceptionCaster', 'castException'],
         'Error' => ['Symfony\Component\VarDumper\Caster\ExceptionCaster', 'castError'],
         'Symfony\Component\DependencyInjection\ContainerInterface' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
+        'Symfony\Component\HttpClient\CurlHttpClient' => ['Symfony\Component\VarDumper\Caster\SymfonyCaster', 'castHttpClient'],
+        'Symfony\Component\HttpClient\NativeHttpClient' => ['Symfony\Component\VarDumper\Caster\SymfonyCaster', 'castHttpClient'],
+        'Symfony\Component\HttpClient\Response\CurlResponse' => ['Symfony\Component\VarDumper\Caster\SymfonyCaster', 'castHttpClient'],
+        'Symfony\Component\HttpClient\Response\NativeResponse' => ['Symfony\Component\VarDumper\Caster\SymfonyCaster', 'castHttpClient'],
         'Symfony\Component\HttpFoundation\Request' => ['Symfony\Component\VarDumper\Caster\SymfonyCaster', 'castRequest'],
         'Symfony\Component\VarDumper\Exception\ThrowingCasterException' => ['Symfony\Component\VarDumper\Caster\ExceptionCaster', 'castThrowingCasterException'],
         'Symfony\Component\VarDumper\Caster\TraceStub' => ['Symfony\Component\VarDumper\Caster\ExceptionCaster', 'castTraceStub'],
diff --git a/src/Symfony/Contracts/CHANGELOG.md b/src/Symfony/Contracts/CHANGELOG.md
index fba42d5954..b37bc2a705 100644
--- a/src/Symfony/Contracts/CHANGELOG.md
+++ b/src/Symfony/Contracts/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+1.1.0
+-----
+
+ * added `HttpClient` namespace with contracts for implementing flexible HTTP clients
+
 1.0.0
 -----
 
diff --git a/src/Symfony/Contracts/HttpClient/ChunkInterface.php b/src/Symfony/Contracts/HttpClient/ChunkInterface.php
new file mode 100644
index 0000000000..bbec2cdfa6
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/ChunkInterface.php
@@ -0,0 +1,66 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient;
+
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+
+/**
+ * The interface of chunks returned by ResponseStreamInterface::current().
+ *
+ * When the chunk is first, last or timeout, the content MUST be empty.
+ * When an unchecked timeout or a network error occurs, a TransportExceptionInterface
+ * MUST be thrown by the destructor unless one was already thrown by another method.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ChunkInterface
+{
+    /**
+     * Tells when the inactivity timeout has been reached.
+     *
+     * @throws TransportExceptionInterface on a network error
+     */
+    public function isTimeout(): bool;
+
+    /**
+     * Tells when headers just arrived.
+     *
+     * @throws TransportExceptionInterface on a network error or when the inactivity timeout is reached
+     */
+    public function isFirst(): bool;
+
+    /**
+     * Tells when the body just completed.
+     *
+     * @throws TransportExceptionInterface on a network error or when the inactivity timeout is reached
+     */
+    public function isLast(): bool;
+
+    /**
+     * Returns the content of the response chunk.
+     *
+     * @throws TransportExceptionInterface on a network error or when the inactivity timeout is reached
+     */
+    public function getContent(): string;
+
+    /**
+     * Returns the offset of the chunk in the response body.
+     */
+    public function getOffset(): int;
+
+    /**
+     * In case of error, returns the message that describes it.
+     */
+    public function getError(): ?string;
+}
diff --git a/src/Symfony/Contracts/HttpClient/Exception/ClientExceptionInterface.php b/src/Symfony/Contracts/HttpClient/Exception/ClientExceptionInterface.php
new file mode 100644
index 0000000000..a5f81dc146
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Exception/ClientExceptionInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Exception;
+
+/**
+ * When a 4xx response is returned.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ClientExceptionInterface extends ExceptionInterface
+{
+}
diff --git a/src/Symfony/Contracts/HttpClient/Exception/ExceptionInterface.php b/src/Symfony/Contracts/HttpClient/Exception/ExceptionInterface.php
new file mode 100644
index 0000000000..6d59715f70
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Exception/ExceptionInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Exception;
+
+/**
+ * The base interface for all exceptions in the contract.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ExceptionInterface extends \Throwable
+{
+}
diff --git a/src/Symfony/Contracts/HttpClient/Exception/RedirectionExceptionInterface.php b/src/Symfony/Contracts/HttpClient/Exception/RedirectionExceptionInterface.php
new file mode 100644
index 0000000000..208d692c62
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Exception/RedirectionExceptionInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Exception;
+
+/**
+ * When a 3xx response is returned and the "max_redirects" option has been reached.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface RedirectionExceptionInterface extends ExceptionInterface
+{
+}
diff --git a/src/Symfony/Contracts/HttpClient/Exception/ServerExceptionInterface.php b/src/Symfony/Contracts/HttpClient/Exception/ServerExceptionInterface.php
new file mode 100644
index 0000000000..a1be7d4f7f
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Exception/ServerExceptionInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Exception;
+
+/**
+ * When a 5xx response is returned.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ServerExceptionInterface extends ExceptionInterface
+{
+}
diff --git a/src/Symfony/Contracts/HttpClient/Exception/TransportExceptionInterface.php b/src/Symfony/Contracts/HttpClient/Exception/TransportExceptionInterface.php
new file mode 100644
index 0000000000..1cdc30a2fc
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Exception/TransportExceptionInterface.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Exception;
+
+/**
+ * When any error happens at the transport level.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface TransportExceptionInterface extends ExceptionInterface
+{
+}
diff --git a/src/Symfony/Contracts/HttpClient/HttpClientInterface.php b/src/Symfony/Contracts/HttpClient/HttpClientInterface.php
new file mode 100644
index 0000000000..8d58e813e8
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/HttpClientInterface.php
@@ -0,0 +1,87 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient;
+
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+use Symfony\Contracts\HttpClient\Test\HttpClientTestCase;
+
+/**
+ * Provides flexible methods for requesting HTTP resources synchronously or asynchronously.
+ *
+ * @see HttpClientTestCase for a reference test suite
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface HttpClientInterface
+{
+    public const OPTIONS_DEFAULTS = [
+        'auth' => null,         // string - a username:password enabling HTTP Basic authentication
+        'query' => [],          // string[] - associative array of query string values to merge with the request's URL
+        'headers' => [],        // iterable|string[]|string[][] - headers names provided as keys or as part of values
+        'body' => '',           // array|string|resource|\Traversable|\Closure - the callback SHOULD yield a string
+                                //   smaller than the amount requested as argument; the empty string signals EOF; when
+                                //   an array is passed, it is meant as a form payload of field names and values
+        'json' => null,         // array|\JsonSerializable - when set, implementations MUST set the "body" option to
+                                //   the JSON-encoded value and set the "content-type" headers to a JSON-compatible
+                                //   value it is they are not defined - typically "application/json"
+        'user_data' => null,    // mixed - any extra data to attach to the request (scalar, callable, object...) that
+                                //         MUST be available via $response->getInfo('data') - not used internally
+        'max_redirects' => 20,  // int - the maximum number of redirects to follow; a value lower or equal to 0 means
+                                //       redirects should not be followed; "Authorization" and "Cookie" headers MUST
+                                //       NOT follow except for the initial host name
+        'http_version' => null, // string - defaults to the best supported version, typically 1.1 or 2.0
+        'base_uri' => null,     // string - the URI to resolve relative URLs, following rules in RFC 3986, section 2
+        'buffer' => true,       // bool - whether the content of the response should be buffered or not
+        'on_progress' => null,  // callable(int $dlNow, int $dlSize, array $info) - throwing any exceptions MUST abort
+                                //      the request; it MUST be called on DNS resolution, on arrival of headers and on
+                                //      completion; it SHOULD be called on upload/download of data and at least 1/s
+        'resolve' => [],        // string[] - a map of host to IP address that SHOULD replace DNS resolution
+        'proxy' => null,        // string - by default, the proxy-related env vars handled by curl SHOULD be honored
+        'no_proxy' => null,     // string - a comma separated list of hosts that do not require a proxy to be reached
+        'timeout' => null,      // float - the inactivity timeout - defaults to ini_get('default_socket_timeout')
+        'bindto' => '0',        // string - the interface or the local socket to bind to
+        'verify_peer' => true,  // see https://php.net/context.ssl for the following options
+        'verify_host' => true,
+        'cafile' => null,
+        'capath' => null,
+        'local_cert' => null,
+        'local_pk' => null,
+        'passphrase' => null,
+        'ciphers' => null,
+        'peer_fingerprint' => null,
+        'capture_peer_cert_chain' => false,
+    ];
+
+    /**
+     * Requests an HTTP resource.
+     *
+     * Responses MUST be lazy, but their status code MUST be
+     * checked even if none of their public methods are called.
+     *
+     * Implementations are not required to support all options described above; they can also
+     * support more custom options; but in any case, they MUST throw a TransportExceptionInterface
+     * when an unsupported option is passed.
+     *
+     * @throws TransportExceptionInterface When an unsupported option is passed
+     */
+    public function request(string $method, string $url, array $options = []): ResponseInterface;
+
+    /**
+     * Yields responses chunk by chunk as they complete.
+     *
+     * @param ResponseInterface|ResponseInterface[]|iterable $responses One or more responses created by the current HTTP client
+     * @param float|null                                     $timeout   The inactivity timeout before exiting the iterator
+     */
+    public function stream($responses, float $timeout = null): ResponseStreamInterface;
+}
diff --git a/src/Symfony/Contracts/HttpClient/ResponseInterface.php b/src/Symfony/Contracts/HttpClient/ResponseInterface.php
new file mode 100644
index 0000000000..7aeed6d510
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/ResponseInterface.php
@@ -0,0 +1,88 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient;
+
+use Symfony\Contracts\HttpClient\Exception\ClientExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\ExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\RedirectionExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\ServerExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+
+/**
+ * A (lazily retrieved) HTTP response.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ResponseInterface
+{
+    /**
+     * Gets the HTTP status code of the response.
+     *
+     * @throws TransportExceptionInterface when a network error occurs
+     */
+    public function getStatusCode(): int;
+
+    /**
+     * Gets the HTTP headers of the response.
+     *
+     * @param bool $throw Whether an exception should be thrown on 3/4/5xx status codes
+     *
+     * @return string[][] The headers of the response keyed by header names in lowercase
+     *
+     * @throws TransportExceptionInterface   When a network error occurs
+     * @throws RedirectionExceptionInterface On a 3xx when $throw is true and the "max_redirects" option has been reached
+     * @throws ClientExceptionInterface      On a 4xx when $throw is true
+     * @throws ServerExceptionInterface      On a 5xx when $throw is true
+     */
+    public function getHeaders(bool $throw = true): array;
+
+    /**
+     * Gets the response body as a string.
+     *
+     * @param bool $throw Whether an exception should be thrown on 3/4/5xx status codes
+     *
+     * @throws TransportExceptionInterface   When a network error occurs
+     * @throws RedirectionExceptionInterface On a 3xx when $throw is true and the "max_redirects" option has been reached
+     * @throws ClientExceptionInterface      On a 4xx when $throw is true
+     * @throws ServerExceptionInterface      On a 5xx when $throw is true
+     */
+    public function getContent(bool $throw = true): string;
+
+    /**
+     * Returns info coming from the transport layer.
+     *
+     * This method SHOULD NOT throw any ExceptionInterface and SHOULD be non-blocking.
+     * The returned info is "live": it can be empty and can change from one call to
+     * another, as the request/response progresses.
+     *
+     * The following info MUST be returned:
+     *  - raw_headers - an array modelled after the special $http_response_header variable
+     *  - redirect_count - the number of redirects followed while executing the request
+     *  - redirect_url - the resolved location of redirect responses, null otherwise
+     *  - start_time - the time when the request was sent or 0.0 when it's pending
+     *  - http_code - the last response code or 0 when it is not known yet
+     *  - error - the error message when the transfer was aborted, null otherwise
+     *  - data - the value of the "data" request option, null if not set
+     *  - url - the last effective URL of the request
+     *
+     * When the "capture_peer_cert_chain" option is true, the "peer_certificate_chain"
+     * attribute SHOULD list the peer certificates as an array of OpenSSL X.509 resources.
+     *
+     * Other info SHOULD be named after curl_getinfo()'s associative return value.
+     *
+     * @return array|mixed|null An array of all available info, or one of them when $type is
+     *                          provided, or null when an unsupported type is requested
+     */
+    public function getInfo(string $type = null);
+}
diff --git a/src/Symfony/Contracts/HttpClient/ResponseStreamInterface.php b/src/Symfony/Contracts/HttpClient/ResponseStreamInterface.php
new file mode 100644
index 0000000000..dfff554dfe
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/ResponseStreamInterface.php
@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient;
+
+/**
+ * Yields response chunks, returned by HttpClientInterface::stream().
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ *
+ * @experimental in 1.1
+ */
+interface ResponseStreamInterface extends \Iterator
+{
+    public function key(): ResponseInterface;
+
+    public function current(): ChunkInterface;
+}
diff --git a/src/Symfony/Contracts/HttpClient/Test/Fixtures/web/index.php b/src/Symfony/Contracts/HttpClient/Test/Fixtures/web/index.php
new file mode 100644
index 0000000000..ec15196c65
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Test/Fixtures/web/index.php
@@ -0,0 +1,124 @@
+<?php
+
+if ('cli-server' !== \PHP_SAPI) {
+    // safe guard against unwanted execution
+    throw new \Exception("You cannot run this script directly, it's a fixture for TestHttpServer.");
+}
+
+$vars = [];
+
+if (!$_POST) {
+    $_POST = json_decode(file_get_contents('php://input'), true);
+    $_POST['content-type'] = $_SERVER['HTTP_CONTENT_TYPE'] ?? '?';
+}
+
+foreach ($_SERVER as $k => $v) {
+    switch ($k) {
+        default:
+            if (0 !== strpos($k, 'HTTP_')) {
+                continue 2;
+            }
+            // no break
+        case 'SERVER_NAME':
+        case 'SERVER_PROTOCOL':
+        case 'REQUEST_URI':
+        case 'REQUEST_METHOD':
+        case 'PHP_AUTH_USER':
+        case 'PHP_AUTH_PW':
+            $vars[$k] = $v;
+    }
+}
+
+switch ($vars['REQUEST_URI']) {
+    default:
+        exit;
+
+    case '/':
+    case '/?a=a&b=b':
+    case 'http://127.0.0.1:8057/':
+    case 'http://localhost:8057/':
+        header('Content-Type: application/json');
+        ob_start('ob_gzhandler');
+        break;
+
+    case '/404':
+        header('Content-Type: application/json', true, 404);
+        break;
+
+    case '/301':
+        if ('Basic Zm9vOmJhcg==' === $vars['HTTP_AUTHORIZATION']) {
+            header('Location: http://127.0.0.1:8057/302', true, 301);
+        }
+        break;
+
+    case '/301/bad-tld':
+        header('Location: http://foo.example.', true, 301);
+        break;
+
+    case '/302':
+        if (!isset($vars['HTTP_AUTHORIZATION'])) {
+            header('Location: http://localhost:8057/', true, 302);
+        }
+        break;
+
+    case '/302/relative':
+        header('Location: ..', true, 302);
+        break;
+
+    case '/307':
+        header('Location: http://localhost:8057/post', true, 307);
+        break;
+
+    case '/length-broken':
+        header('Content-Length: 1000');
+        break;
+
+    case '/post':
+        $output = json_encode($_POST + ['REQUEST_METHOD' => $vars['REQUEST_METHOD']], JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
+        header('Content-Type: application/json', true);
+        header('Content-Length: '.\strlen($output));
+        echo $output;
+        exit;
+
+    case '/timeout-header':
+        usleep(300000);
+        break;
+
+    case '/timeout-body':
+        echo '<1>';
+        ob_flush();
+        flush();
+        usleep(500000);
+        echo '<2>';
+        exit;
+
+    case '/timeout-long':
+        ignore_user_abort(false);
+        sleep(1);
+        while (true) {
+            echo '<1>';
+            ob_flush();
+            flush();
+            usleep(500);
+        }
+        exit;
+
+    case '/chunked':
+        header('Transfer-Encoding: chunked');
+        echo "8\r\nSymfony \r\n5\r\nis aw\r\n6\r\nesome!\r\n0\r\n\r\n";
+        exit;
+
+    case '/chunked-broken':
+        header('Transfer-Encoding: chunked');
+        echo "8\r\nSymfony \r\n5\r\nis aw\r\n6\r\ne";
+        exit;
+
+    case '/gzip-broken':
+        header('Content-Encoding: gzip');
+        echo str_repeat('-', 1000);
+        exit;
+}
+
+header('Content-Type: application/json', true);
+
+echo json_encode($vars, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
diff --git a/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php b/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php
new file mode 100644
index 0000000000..59703d0ffb
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php
@@ -0,0 +1,677 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Test;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Contracts\HttpClient\Exception\ClientExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\RedirectionExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+/**
+ * A reference test suite for HttpClientInterface implementations.
+ *
+ * @experimental in 1.1
+ */
+abstract class HttpClientTestCase extends TestCase
+{
+    private static $server;
+
+    public static function setUpBeforeClass()
+    {
+        TestHttpServer::start();
+    }
+
+    abstract protected function getHttpClient(): HttpClientInterface;
+
+    public function testGetRequest()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057', [
+            'headers' => ['Foo' => 'baR'],
+            'user_data' => $data = new \stdClass(),
+        ]);
+
+        $this->assertSame([], $response->getInfo('raw_headers'));
+        $this->assertSame($data, $response->getInfo()['user_data']);
+        $this->assertSame(200, $response->getStatusCode());
+
+        $info = $response->getInfo();
+        $this->assertNull($info['error']);
+        $this->assertSame(0, $info['redirect_count']);
+        $this->assertSame('HTTP/1.1 200 OK', $info['raw_headers'][0]);
+        $this->assertSame('Host: localhost:8057', $info['raw_headers'][1]);
+        $this->assertSame('http://localhost:8057/', $info['url']);
+
+        $headers = $response->getHeaders();
+
+        $this->assertSame('localhost:8057', $headers['host'][0]);
+        $this->assertSame(['application/json'], $headers['content-type']);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame('HTTP/1.1', $body['SERVER_PROTOCOL']);
+        $this->assertSame('/', $body['REQUEST_URI']);
+        $this->assertSame('GET', $body['REQUEST_METHOD']);
+        $this->assertSame('localhost:8057', $body['HTTP_HOST']);
+        $this->assertSame('baR', $body['HTTP_FOO']);
+
+        $response = $client->request('GET', 'http://localhost:8057/length-broken');
+
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+
+    public function testNonBufferedGetRequest()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057', [
+            'buffer' => false,
+            'headers' => ['Foo' => 'baR'],
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('baR', $body['HTTP_FOO']);
+
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+
+    public function testUnsupportedOption()
+    {
+        $client = $this->getHttpClient();
+
+        $this->expectException(\InvalidArgumentException::class);
+        $client->request('GET', 'http://localhost:8057', [
+            'capture_peer_cert' => 1.0,
+        ]);
+    }
+
+    public function testHttpVersion()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057', [
+            'http_version' => 1.0,
+        ]);
+
+        $this->assertSame(200, $response->getStatusCode());
+        $this->assertSame('HTTP/1.0 200 OK', $response->getInfo('raw_headers')[0]);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame('HTTP/1.0', $body['SERVER_PROTOCOL']);
+        $this->assertSame('GET', $body['REQUEST_METHOD']);
+        $this->assertSame('/', $body['REQUEST_URI']);
+    }
+
+    public function testChunkedEncoding()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/chunked');
+
+        $this->assertSame(['chunked'], $response->getHeaders()['transfer-encoding']);
+        $this->assertSame('Symfony is awesome!', $response->getContent());
+
+        $response = $client->request('GET', 'http://localhost:8057/chunked-broken');
+
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+
+    public function testClientError()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/404');
+
+        $client->stream($response)->valid();
+
+        $this->assertSame(404, $response->getInfo('http_code'));
+
+        try {
+            $response->getHeaders();
+            $this->fail(ClientExceptionInterface::class.' expected');
+        } catch (ClientExceptionInterface $e) {
+        }
+
+        try {
+            $response->getContent();
+            $this->fail(ClientExceptionInterface::class.' expected');
+        } catch (ClientExceptionInterface $e) {
+        }
+
+        $this->assertSame(404, $response->getStatusCode());
+        $this->assertSame(['application/json'], $response->getHeaders(false)['content-type']);
+        $this->assertNotEmpty($response->getContent(false));
+    }
+
+    public function testIgnoreErrors()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/404');
+
+        $this->assertSame(404, $response->getStatusCode());
+    }
+
+    public function testDnsError()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/301/bad-tld');
+
+        try {
+            $response->getStatusCode();
+            $this->fail(TransportExceptionInterface::class.' expected');
+        } catch (TransportExceptionInterface $e) {
+            $this->addToAssertionCount(1);
+        }
+
+        try {
+            $response->getStatusCode();
+            $this->fail(TransportExceptionInterface::class.' still expected');
+        } catch (TransportExceptionInterface $e) {
+            $this->addToAssertionCount(1);
+        }
+
+        $response = $client->request('GET', 'http://localhost:8057/301/bad-tld');
+
+        try {
+            foreach ($client->stream($response) as $r => $chunk) {
+            }
+            $this->fail(TransportExceptionInterface::class.' expected');
+        } catch (TransportExceptionInterface $e) {
+            $this->addToAssertionCount(1);
+        }
+
+        $this->assertSame($response, $r);
+        $this->assertNotNull($chunk->getError());
+
+        foreach ($client->stream($response) as $chunk) {
+            $this->fail('Already errored responses shouldn\'t be yielded');
+        }
+    }
+
+    public function testInlineAuth()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://foo:bar%3Dbar@localhost:8057');
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame('foo', $body['PHP_AUTH_USER']);
+        $this->assertSame('bar=bar', $body['PHP_AUTH_PW']);
+    }
+
+    public function testRedirects()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('POST', 'http://localhost:8057/301', [
+            'auth' => 'foo:bar',
+            'body' => 'foo=bar',
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('GET', $body['REQUEST_METHOD']);
+        $this->assertSame('Basic Zm9vOmJhcg==', $body['HTTP_AUTHORIZATION']);
+        $this->assertSame('http://localhost:8057/', $response->getInfo('url'));
+
+        $this->assertSame(2, $response->getInfo('redirect_count'));
+        $this->assertNull($response->getInfo('redirect_url'));
+
+        $expected = [
+            'HTTP/1.1 301 Moved Permanently',
+            'Location: http://127.0.0.1:8057/302',
+            'Content-Type: application/json',
+            'HTTP/1.1 302 Found',
+            'Location: http://localhost:8057/',
+            'Content-Type: application/json',
+            'HTTP/1.1 200 OK',
+            'Content-Type: application/json',
+        ];
+
+        $filteredHeaders = array_intersect($expected, $response->getInfo('raw_headers'));
+
+        $this->assertSame($expected, $filteredHeaders);
+    }
+
+    public function testRelativeRedirects()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/302/relative');
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('/', $body['REQUEST_URI']);
+        $this->assertNull($response->getInfo('redirect_url'));
+
+        $response = $client->request('GET', 'http://localhost:8057/302/relative', [
+            'max_redirects' => 0,
+        ]);
+
+        $this->assertSame(302, $response->getStatusCode());
+        $this->assertSame('http://localhost:8057/', $response->getInfo('redirect_url'));
+    }
+
+    public function testRedirect307()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('POST', 'http://localhost:8057/307', [
+            'body' => 'foo=bar',
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame(['foo' => 'bar', 'REQUEST_METHOD' => 'POST'], $body);
+    }
+
+    public function testMaxRedirects()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/301', [
+            'max_redirects' => 1,
+            'auth' => 'foo:bar',
+        ]);
+
+        try {
+            $response->getHeaders();
+            $this->fail(RedirectionExceptionInterface::class.' expected');
+        } catch (RedirectionExceptionInterface $e) {
+        }
+
+        $this->assertSame(302, $response->getStatusCode());
+        $this->assertSame(1, $response->getInfo('redirect_count'));
+        $this->assertSame('http://localhost:8057/', $response->getInfo('redirect_url'));
+
+        $expected = [
+            'HTTP/1.1 301 Moved Permanently',
+            'Location: http://127.0.0.1:8057/302',
+            'Content-Type: application/json',
+            'HTTP/1.1 302 Found',
+            'Location: http://localhost:8057/',
+            'Content-Type: application/json',
+        ];
+
+        $filteredHeaders = array_intersect($expected, $response->getInfo('raw_headers'));
+
+        $this->assertSame($expected, $filteredHeaders);
+    }
+
+    public function testStream()
+    {
+        $client = $this->getHttpClient();
+
+        $response = $client->request('GET', 'http://localhost:8057');
+        $chunks = $client->stream($response);
+        $result = [];
+
+        foreach ($chunks as $r => $chunk) {
+            if ($chunk->isTimeout()) {
+                $result[] = 't';
+            } elseif ($chunk->isLast()) {
+                $result[] = 'l';
+            } elseif ($chunk->isFirst()) {
+                $result[] = 'f';
+            }
+        }
+
+        $this->assertSame($response, $r);
+        $this->assertSame(['f', 'l'], $result);
+    }
+
+    public function testAddToStream()
+    {
+        $client = $this->getHttpClient();
+
+        $r1 = $client->request('GET', 'http://localhost:8057');
+
+        $completed = [];
+
+        $pool = [$r1];
+
+        while ($pool) {
+            $chunks = $client->stream($pool);
+            $pool = [];
+
+            foreach ($chunks as $r => $chunk) {
+                if (!$chunk->isLast()) {
+                    continue;
+                }
+
+                if ($r1 === $r) {
+                    $r2 = $client->request('GET', 'http://localhost:8057');
+                    $pool[] = $r2;
+                }
+
+                $completed[] = $r;
+            }
+        }
+
+        $this->assertSame([$r1, $r2], $completed);
+    }
+
+    public function testCompleteTypeError()
+    {
+        $client = $this->getHttpClient();
+
+        $this->expectException(\TypeError::class);
+        $client->stream(123);
+    }
+
+    public function testOnProgress()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('POST', 'http://localhost:8057/post', [
+            'headers' => ['Content-Length' => 14],
+            'body' => 'foo=0123456789',
+            'on_progress' => function (...$state) use (&$steps) { $steps[] = $state; },
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame(['foo' => '0123456789', 'REQUEST_METHOD' => 'POST'], $body);
+        $this->assertSame([0, 0], \array_slice($steps[0], 0, 2));
+        $lastStep = \array_slice($steps, -1)[0];
+        $this->assertSame([57, 57], \array_slice($lastStep, 0, 2));
+        $this->assertSame('http://localhost:8057/post', $steps[0][2]['url']);
+    }
+
+    public function testPostArray()
+    {
+        $client = $this->getHttpClient();
+
+        $response = $client->request('POST', 'http://localhost:8057/post', [
+            'body' => ['foo' => 'bar'],
+        ]);
+
+        $this->assertSame(['foo' => 'bar', 'REQUEST_METHOD' => 'POST'], json_decode($response->getContent(), true));
+    }
+
+    public function testPostResource()
+    {
+        $client = $this->getHttpClient();
+
+        $h = fopen('php://temp', 'w+');
+        fwrite($h, 'foo=0123456789');
+        rewind($h);
+
+        $response = $client->request('POST', 'http://localhost:8057/post', [
+            'body' => $h,
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertSame(['foo' => '0123456789', 'REQUEST_METHOD' => 'POST'], $body);
+    }
+
+    public function testPostCallback()
+    {
+        $client = $this->getHttpClient();
+
+        $response = $client->request('POST', 'http://localhost:8057/post', [
+            'body' => function () {
+                yield 'foo';
+                yield '=';
+                yield '0123456789';
+            },
+        ]);
+
+        $this->assertSame(['foo' => '0123456789', 'REQUEST_METHOD' => 'POST'], json_decode($response->getContent(), true));
+    }
+
+    public function testOnProgressCancel()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/timeout-body', [
+            'on_progress' => function ($dlNow) {
+                if (0 < $dlNow) {
+                    throw new \Exception('Aborting the request');
+                }
+            },
+        ]);
+
+        try {
+            foreach ($client->stream([$response]) as $chunk) {
+            }
+            $this->fail(ClientExceptionInterface::class.' expected');
+        } catch (TransportExceptionInterface $e) {
+            $this->assertSame('Aborting the request', $e->getPrevious()->getMessage());
+        }
+
+        $this->assertNotNull($response->getInfo('error'));
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+
+    public function testOnProgressError()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/timeout-body', [
+            'on_progress' => function ($dlNow) {
+                if (0 < $dlNow) {
+                    throw new \Error('BUG');
+                }
+            },
+        ]);
+
+        try {
+            foreach ($client->stream([$response]) as $chunk) {
+            }
+            $this->fail('Error expected');
+        } catch (\Error $e) {
+            $this->assertSame('BUG', $e->getMessage());
+        }
+
+        $this->assertNotNull($response->getInfo('error'));
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+
+    public function testResolve()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://symfony.com:8057/', [
+            'resolve' => ['symfony.com' => '127.0.0.1'],
+        ]);
+
+        $this->assertSame(200, $response->getStatusCode());
+        $this->assertSame(200, $client->request('GET', 'http://symfony.com:8057/')->getStatusCode());
+
+        $response = null;
+        $this->expectException(TransportExceptionInterface::class);
+        $client->request('GET', 'http://symfony.com:8057/');
+    }
+
+    public function testTimeoutOnAccess()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/timeout-header', [
+            'timeout' => 0.1,
+        ]);
+
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getHeaders();
+    }
+
+    public function testTimeoutOnStream()
+    {
+        usleep(300000); // wait for the previous test to release the server
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/timeout-body');
+
+        $this->assertSame(200, $response->getStatusCode());
+        $chunks = $client->stream([$response], 0.2);
+
+        $result = [];
+
+        foreach ($chunks as $r => $chunk) {
+            if ($chunk->isTimeout()) {
+                $result[] = 't';
+            } else {
+                $result[] = $chunk->getContent();
+            }
+        }
+
+        $this->assertSame(['<1>', 't'], $result);
+
+        $chunks = $client->stream([$response]);
+
+        foreach ($chunks as $r => $chunk) {
+            $this->assertSame('<2>', $chunk->getContent());
+            $this->assertSame('<1><2>', $r->getContent());
+
+            return;
+        }
+
+        $this->fail('The response should have completed');
+    }
+
+    public function testUncheckedTimeoutThrows()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/timeout-body');
+        $chunks = $client->stream([$response], 0.1);
+
+        $this->expectException(TransportExceptionInterface::class);
+
+        foreach ($chunks as $r => $chunk) {
+        }
+    }
+
+    public function testDestruct()
+    {
+        $client = $this->getHttpClient();
+
+        $downloaded = 0;
+        $start = microtime(true);
+        $client->request('GET', 'http://localhost:8057/timeout-long');
+        $client = null;
+        $duration = microtime(true) - $start;
+
+        $this->assertGreaterThan(1, $duration);
+        $this->assertLessThan(3, $duration);
+    }
+
+    public function testProxy()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/', [
+            'proxy' => 'http://localhost:8057',
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('localhost:8057', $body['HTTP_HOST']);
+        $this->assertRegexp('#^http://(localhost|127\.0\.0\.1):8057/$#', $body['REQUEST_URI']);
+
+        $response = $client->request('GET', 'http://localhost:8057/', [
+            'proxy' => 'http://foo:b%3Dar@localhost:8057',
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('Basic Zm9vOmI9YXI=', $body['HTTP_PROXY_AUTHORIZATION']);
+    }
+
+    public function testNoProxy()
+    {
+        putenv('no_proxy='.$_SERVER['no_proxy'] = 'example.com, localhost');
+
+        try {
+            $client = $this->getHttpClient();
+            $response = $client->request('GET', 'http://localhost:8057/', [
+                'proxy' => 'http://localhost:8057',
+            ]);
+
+            $body = json_decode($response->getContent(), true);
+
+            $this->assertSame('HTTP/1.1', $body['SERVER_PROTOCOL']);
+            $this->assertSame('/', $body['REQUEST_URI']);
+            $this->assertSame('GET', $body['REQUEST_METHOD']);
+        } finally {
+            putenv('no_proxy');
+            unset($_SERVER['no_proxy']);
+        }
+    }
+
+    /**
+     * @requires extension zlib
+     */
+    public function testAutoEncodingRequest()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057');
+
+        $this->assertSame(200, $response->getStatusCode());
+
+        $headers = $response->getHeaders();
+
+        $this->assertSame(['Accept-Encoding'], $headers['vary']);
+        $this->assertContains('gzip', $headers['content-encoding'][0]);
+
+        $body = json_decode($response->getContent(), true);
+
+        $this->assertContains('gzip', $body['HTTP_ACCEPT_ENCODING']);
+    }
+
+    public function testBaseUri()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', '../404', [
+            'base_uri' => 'http://localhost:8057/abc/',
+        ]);
+
+        $this->assertSame(404, $response->getStatusCode());
+        $this->assertSame(['application/json'], $response->getHeaders(false)['content-type']);
+    }
+
+    public function testQuery()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/?a=a', [
+            'query' => ['b' => 'b'],
+        ]);
+
+        $body = json_decode($response->getContent(), true);
+        $this->assertSame('GET', $body['REQUEST_METHOD']);
+        $this->assertSame('/?a=a&b=b', $body['REQUEST_URI']);
+    }
+
+    /**
+     * @requires extension zlib
+     */
+    public function testUserlandEncodingRequest()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057', [
+            'headers' => ['Accept-Encoding' => 'gzip'],
+        ]);
+
+        $headers = $response->getHeaders();
+
+        $this->assertSame(['Accept-Encoding'], $headers['vary']);
+        $this->assertContains('gzip', $headers['content-encoding'][0]);
+
+        $body = $response->getContent();
+
+        $this->assertSame("\x1F", $body[0]);
+        $body = json_decode(gzdecode($body), true);
+
+        $this->assertSame('gzip', $body['HTTP_ACCEPT_ENCODING']);
+    }
+
+    /**
+     * @requires extension zlib
+     */
+    public function testGzipBroken()
+    {
+        $client = $this->getHttpClient();
+        $response = $client->request('GET', 'http://localhost:8057/gzip-broken');
+
+        $this->expectException(TransportExceptionInterface::class);
+        $response->getContent();
+    }
+}
diff --git a/src/Symfony/Contracts/HttpClient/Test/TestHttpServer.php b/src/Symfony/Contracts/HttpClient/Test/TestHttpServer.php
new file mode 100644
index 0000000000..5b05f50562
--- /dev/null
+++ b/src/Symfony/Contracts/HttpClient/Test/TestHttpServer.php
@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\HttpClient\Test;
+
+use Symfony\Component\Process\PhpExecutableFinder;
+use Symfony\Component\Process\Process;
+
+/**
+ * @experimental in 1.1
+ */
+class TestHttpServer
+{
+    private static $server;
+
+    public static function start()
+    {
+        if (null !== self::$server) {
+            return;
+        }
+
+        $spec = [
+            1 => ['file', '\\' === \DIRECTORY_SEPARATOR ? 'NUL' : '/dev/null', 'w'],
+            2 => ['file', '\\' === \DIRECTORY_SEPARATOR ? 'NUL' : '/dev/null', 'w'],
+        ];
+
+        $finder = new PhpExecutableFinder();
+        $process = new Process(array_merge([$finder->find(false)], $finder->findArguments(), ['-dopcache.enable=0', '-dvariables_order=EGPCS', '-S', '127.0.0.1:8057']));
+        $process->setWorkingDirectory(__DIR__.'/Fixtures/web');
+        $process->setTimeout(300);
+        $process->start();
+
+        self::$server = new class() {
+            public $process;
+
+            public function __destruct()
+            {
+                $this->process->stop();
+            }
+        };
+
+        self::$server->process = $process;
+
+        sleep('\\' === \DIRECTORY_SEPARATOR ? 10 : 1);
+    }
+}
diff --git a/src/Symfony/Contracts/composer.json b/src/Symfony/Contracts/composer.json
index b01744783f..f881258dc1 100644
--- a/src/Symfony/Contracts/composer.json
+++ b/src/Symfony/Contracts/composer.json
@@ -20,12 +20,14 @@
     },
     "require-dev": {
         "psr/cache": "^1.0",
-        "psr/container": "^1.0"
+        "psr/container": "^1.0",
+        "symfony/polyfill-intl-idn": "^1.10"
     },
     "suggest": {
         "psr/cache": "When using the Cache contracts",
         "psr/container": "When using the Service contracts",
         "symfony/cache-contracts-implementation": "",
+        "symfony/http-client-contracts-implementation": "",
         "symfony/service-contracts-implementation": "",
         "symfony/translation-contracts-implementation": ""
     },