diff --git a/src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php b/src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php
index c81c7a6c7a..d040b13277 100644
--- a/src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php
+++ b/src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php
@@ -1,163 +1,172 @@
 <?php
 
 /*
  * Copyright 2011 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 /**
  * @group aphront
  */
 class AphrontDefaultApplicationConfiguration
   extends AphrontApplicationConfiguration {
 
   public function getApplicationName() {
     return 'aphront-default';
   }
 
   public function getURIMap() {
     return array(
       '/repository/' => array(
         '$'                     => 'RepositoryListController',
         'new/$'                 => 'RepositoryEditController',
         'edit/(?<id>\d+)/$'     => 'RepositoryEditController',
         'delete/(?<id>\d+)/$'   => 'RepositoryDeleteController',
       ),
       '/' => array(
         '$'                     => 'PhabricatorDirectoryMainController',
       ),
       '/directory/' => array(
         'item/$'
           => 'PhabricatorDirectoryItemListController',
         'item/edit/(?:(?<id>\d+)/)?$'
           => 'PhabricatorDirectoryItemEditController',
         'item/delete/(?<id>\d+)/'
           => 'PhabricatorDirectoryItemDeleteController',
         'category/$'
           => 'PhabricatorDirectoryCategoryListController',
         'category/edit/(?:(?<id>\d+)/)?$'
           => 'PhabricatorDirectoryCategoryEditController',
         'category/delete/(?<id>\d+)/'
           => 'PhabricatorDirectoryCategoryDeleteController',
       ),
       '/file/' => array(
         '$' => 'PhabricatorFileListController',
         'upload/$' => 'PhabricatorFileUploadController',
         '(?<view>info)/(?<phid>[^/]+)/' => 'PhabricatorFileViewController',
         '(?<view>view)/(?<phid>[^/]+)/' => 'PhabricatorFileViewController',
         '(?<view>download)/(?<phid>[^/]+)/' => 'PhabricatorFileViewController',
       ),
       '/phid/' => array(
         '$' => 'PhabricatorPHIDLookupController',
         'list/$' => 'PhabricatorPHIDListController',
         'type/$' => 'PhabricatorPHIDTypeListController',
         'type/edit/(?:(?<id>\d+)/)?$' => 'PhabricatorPHIDTypeEditController',
         'new/$' => 'PhabricatorPHIDAllocateController',
       ),
       '/people/' => array(
         '$' => 'PhabricatorPeopleListController',
         'edit/(?:(?<username>\w+)/)?$' => 'PhabricatorPeopleEditController',
       ),
       '/p/(?<username>\w+)/$' => 'PhabricatorPeopleProfileController',
       '/conduit/' => array(
         '$' => 'PhabricatorConduitConsoleController',
         'method/(?<method>[^/]+)$' => 'PhabricatorConduitConsoleController',
         'log/$' => 'PhabricatorConduitLogController',
       ),
       '/api/(?<method>[^/]+)$' => 'PhabricatorConduitAPIController',
 
 
       '/D(?<id>\d+)' => 'DifferentialRevisionViewController',
       '/differential/' => array(
         '$' => 'DifferentialRevisionListController',
         'filter/(?<filter>\w+)/$' => 'DifferentialRevisionListController',
         'diff/(?<id>\d+)/$'       => 'DifferentialDiffViewController',
         'changeset/(?<id>\d+)/$'  => 'DifferentialChangesetViewController',
         'revision/edit/(?:(?<id>\d+)/)?$'
           => 'DifferentialRevisionEditController',
       ),
 
       '/res/' => array(
         '(?<package>pkg/)?(?<hash>[a-f0-9]{8})/(?<path>.+\.(?:css|js))$'
           => 'CelerityResourceController',
       ),
 
       '/typeahead/' => array(
         'common/(?<type>\w+)/$'
           => 'PhabricatorTypeaheadCommonDatasourceController',
       ),
 
       '/mail/' => array(
         '$' => 'PhabricatorMetaMTAListController',
         'send/$' => 'PhabricatorMetaMTASendController',
         'view/(?<id>\d+)/$' => 'PhabricatorMetaMTAViewController',
         'lists/$' => 'PhabricatorMetaMTAMailingListsController',
         'lists/edit/(?:(?<id>\d+)/)?$'
           => 'PhabricatorMetaMTAMailingListEditController',
       ),
 
       '/login/' => 'PhabricatorLoginController',
     );
   }
 
   public function buildRequest() {
     $request = new AphrontRequest($this->getHost(), $this->getPath());
     $request->setRequestData($_GET + $_POST);
     return $request;
   }
 
   public function handleException(Exception $ex) {
 
     $class    = phutil_escape_html(get_class($ex));
     $message  = phutil_escape_html($ex->getMessage());
 
     $content =
       '<div class="aphront-unhandled-exception">'.
         '<h1>Unhandled Exception "'.$class.'": '.$message.'</h1>'.
         '<code>'.phutil_escape_html((string)$ex).'</code>'.
       '</div>';
 
     $view = new PhabricatorStandardPageView();
     $view->appendChild($content);
 
     $response = new AphrontWebpageResponse();
     $response->setContent($view->render());
 
     return $response;
   }
 
   public function willSendResponse(AphrontResponse $response) {
     $request = $this->getRequest();
     if ($response instanceof AphrontDialogResponse) {
       if (!$request->isAjax()) {
         $view = new PhabricatorStandardPageView();
         $view->appendChild(
           '<div style="padding: 2em 0;">'.
             $response->buildResponseString().
           '</div>');
         $response = new AphrontWebpageResponse();
         $response->setContent($view->render());
         return $response;
       }
+    } else if ($response instanceof Aphront404Response) {
+      $view = new PhabricatorStandardPageView();
+      $view->appendChild('404 Not Found');
+      $view->setTitle('404 Not Found');
+      
+      $response = new AphrontWebpageResponse();
+      $response->setContent($view->render());
+      $response->setHTTPResponseCode(404);
+      return $response;
     }
 
     return $response;
   }
 
   public function build404Controller() {
-    return new Phabricator404Controller($request);
+    return array(new Phabricator404Controller($this->getRequest()), array());
   }
 
 
 }
diff --git a/src/aphront/default/configuration/__init__.php b/src/aphront/default/configuration/__init__.php
index f841860f69..66935aa326 100644
--- a/src/aphront/default/configuration/__init__.php
+++ b/src/aphront/default/configuration/__init__.php
@@ -1,17 +1,18 @@
 <?php
 /**
  * This file is automatically generated. Lint this module to rebuild it.
  * @generated
  */
 
 
 
 phutil_require_module('phabricator', 'aphront/applicationconfiguration');
 phutil_require_module('phabricator', 'aphront/request');
 phutil_require_module('phabricator', 'aphront/response/webpage');
+phutil_require_module('phabricator', 'applications/base/controller/404');
 phutil_require_module('phabricator', 'view/page/standard');
 
 phutil_require_module('phutil', 'markup');
 
 
 phutil_require_source('AphrontDefaultApplicationConfiguration.php');
diff --git a/src/aphront/response/base/AphrontResponse.php b/src/aphront/response/base/AphrontResponse.php
index 29a371c08d..c8ea750562 100644
--- a/src/aphront/response/base/AphrontResponse.php
+++ b/src/aphront/response/base/AphrontResponse.php
@@ -1,61 +1,71 @@
 <?php
 
 /*
  * Copyright 2011 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 /**
  * @group aphront
  */
 abstract class AphrontResponse {
 
   private $request;
   private $cacheable = false;
+  private $responseCode = 200;
 
   public function setRequest($request) {
     $this->request = $request;
     return $this;
   }
 
   public function getRequest() {
     return $this->request;
   }
 
   public function getHeaders() {
     return array();
   }
   
   public function setCacheDurationInSeconds($duration) {
     $this->cacheable = $duration;
     return $this;
   }
+  
+  public function setHTTPResponseCode($code) {
+    $this->responseCode = $code;
+    return $this;
+  }
+  
+  public function getHTTPResponseCode() {
+    return $this->responseCode;
+  }
 
   public function getCacheHeaders() {
     if ($this->cacheable) {
       $epoch = time() + $this->cacheable;
       return array(
         array('Expires',       gmdate('D, d M Y H:i:s', $epoch) . ' GMT'),
       );
     } else {
       return array(
         array('Cache-Control', 'private, no-cache, no-store, must-revalidate'),
         array('Expires',       'Sat, 01 Jan 2000 00:00:00 GMT'),
       );
     }
   }
 
   abstract public function buildResponseString();
 
 }
diff --git a/src/applications/base/controller/404/__init__.php b/src/applications/base/controller/404/__init__.php
new file mode 100644
index 0000000000..e3accbe46e
--- /dev/null
+++ b/src/applications/base/controller/404/__init__.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'aphront/response/404');
+phutil_require_module('phabricator', 'applications/base/controller/base');
+
+
+phutil_require_source('Phabricator404Controller.php');
diff --git a/webroot/index.php b/webroot/index.php
index ca2a0ab82d..006c8538cb 100644
--- a/webroot/index.php
+++ b/webroot/index.php
@@ -1,92 +1,98 @@
 <?php
 
 /*
  * Copyright 2011 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 setup_aphront_basics();
 
 $host = $_SERVER['HTTP_HOST'];
 $path = $_REQUEST['__path__'];
 
 // Based on the host and path, choose which application should serve the
 // request. The default is the Aphront demo, but you'll want to replace this
 // with whichever other applications you're running.
 
 switch ($host) {
   default:
     phutil_require_module('phutil', 'autoload');
     phutil_autoload_class('AphrontDefaultApplicationConfiguration');
     $application = new AphrontDefaultApplicationConfiguration();
     break;
 }
 
 $application->setHost($host);
 $application->setPath($path);
 $request = $application->buildRequest();
 $application->setRequest($request);
 list($controller, $uri_data) = $application->buildController();
 try {
   $controller->willBeginExecution();
 
   $controller->willProcessRequest($uri_data);
   $response = $controller->processRequest();
 } catch (AphrontRedirectException $ex) {
   $response = id(new AphrontRedirectResponse())
     ->setURI($ex->getURI());
 } catch (Exception $ex) {
   $response = $application->handleException($ex);
 }
 
 $response = $application->willSendResponse($response);
 
 $response->setRequest($request);
 
 $response_string = $response->buildResponseString();
+
+$code = $response->getHTTPResponseCode();
+if ($code != 200) {
+  header("HTTP/1.0 {$code}");
+}
+
 $headers = $response->getCacheHeaders();
 $headers = array_merge($headers, $response->getHeaders());
 foreach ($headers as $header) {
   list($header, $value) = $header;
   header("{$header}: {$value}");
 }
 echo $response_string;
 
 
 /**
  * @group aphront
  */
 function setup_aphront_basics() {
   $aphront_root   = dirname(dirname(__FILE__));
   $libraries_root = dirname($aphront_root);
 
   ini_set('include_path', ini_get('include_path').':'.$libraries_root.'/');
   @include_once 'libphutil/src/__phutil_library_init__.php';
   if (!@constant('__LIBPHUTIL__')) {
     echo "ERROR: Unable to load libphutil. Update your PHP 'include_path' to ".
          "include the parent directory of libphutil/.\n";
     exit(1);
   }
 
   if (!ini_get('date.timezone')) {
     date_default_timezone_set('America/Los_Angeles');
   }
 
   phutil_load_library($libraries_root.'/arcanist/src');
   phutil_load_library($aphront_root.'/src');
 }
 
 function __autoload($class_name) {
   PhutilSymbolLoader::loadClass($class_name);
 }