diff --git a/developer_manual/app/appdata.rst b/developer_manual/app/appdata.rst
new file mode 100644
index 000000000..a09b2e1ca
--- /dev/null
+++ b/developer_manual/app/appdata.rst
@@ -0,0 +1,45 @@
+=======
+AppData
+=======
+
+.. sectionauthor:: Roeland Jago Douma <roeland@famdouma.nl>
+
+Often an app wants to store data. However not all data that is stored belongs with the users files.
+Often you just want a very simple storage to have some temp files. In order to facilitate this there
+is the AppData folder that provides each app with a private simple filesystem.
+
+Usage is almost trivial when your app is using the AppFramework.
+
+.. code-block:: php
+
+   <?php
+
+   namespace OCA\MyApp\Controller\MyController;
+
+   use OCP\AppFramework\Controller;
+   use OCP\Files\IAppData;
+   use OCP\IRequest;
+
+   class MyController extends Controller {
+       /** @var IAppData */
+       private $appData;
+
+       public function __construct($appName,
+                                   IRequest $request,
+                                   IAppData $appData) {
+           parent::__construct($appName, $request);
+           $this->appData = $appData;
+       }
+   }
+
+This gives your controller access to the IAppData simple filesystem of your app.
+
+The Simple Filesystem
+=====================
+
+The `IAppData` uses the simple filesystem. This is a very simplified filesystem that will allow for easy
+mapping to for example memcaches. The filesystem has three elements: `root`, `folder`, `file`.
+
+The `root` can only contain folders. And each folder can only contain a files. This is limited to keep
+things simple and to allow easy mapping to other backends. For example a sysadmin might chose to map the
+avatars to fast storage since they are used often.
diff --git a/developer_manual/app/index.rst b/developer_manual/app/index.rst
index 500ecb77b..67695f567 100644
--- a/developer_manual/app/index.rst
+++ b/developer_manual/app/index.rst
@@ -28,6 +28,7 @@
    database
    configuration
    filesystem
+   appdata
    users
    two-factor-provider
    hooks