diff --git a/lib/clientexception.php b/lib/clientexception.php
new file mode 100644
index 0000000000..3020d7f506
--- /dev/null
+++ b/lib/clientexception.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * Laconica, the distributed open-source microblogging tool
+ *
+ * class for a client exception (user error)
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Exception
+ * @package   Laconica
+ * @author    Evan Prodromou <evan@controlyourself.ca>
+ * @copyright 2008 Control Yourself, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://laconi.ca/
+ */
+
+if (!defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Class for client exceptions
+ *
+ * Subclass of PHP Exception for user errors.
+ *
+ * @category Exception
+ * @package  Laconica
+ * @author   Evan Prodromou <evan@controlyourself.ca>
+ * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link     http://laconi.ca/
+ */
+
+class ClientException extends Exception
+{
+    public function __construct($message = null, $code = 400) {
+        parent::__construct($message, $code);
+    }
+
+    // custom string representation of object
+    public function __toString() {
+        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
+    }
+}
diff --git a/lib/serverexception.php b/lib/serverexception.php
new file mode 100644
index 0000000000..b8ed6846e7
--- /dev/null
+++ b/lib/serverexception.php
@@ -0,0 +1,55 @@
+<?php
+/**
+ * Laconica, the distributed open-source microblogging tool
+ *
+ * class for a server exception (user error)
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Exception
+ * @package   Laconica
+ * @author    Evan Prodromou <evan@controlyourself.ca>
+ * @copyright 2008 Control Yourself, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://laconi.ca/
+ */
+
+if (!defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Class for server exceptions
+ *
+ * Subclass of PHP Exception for server errors. The user typically can't fix these.
+ *
+ * @category Exception
+ * @package  Laconica
+ * @author   Evan Prodromou <evan@controlyourself.ca>
+ * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link     http://laconi.ca/
+ */
+
+class ServerException extends Exception
+{
+    public function __construct($message = null, $code = 400) {
+        parent::__construct($message, $code);
+    }
+
+    public function __toString() {
+        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
+    }
+}