diff --git a/developer_manual/client_apis/ClientIntegration/index.rst b/developer_manual/client_apis/ClientIntegration/index.rst
new file mode 100644
index 00000000000..1ba1cbdea8f
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+++ b/developer_manual/client_apis/ClientIntegration/index.rst
@@ -0,0 +1,100 @@
+.. _clientintegrationindex:
+
+==================
+Client Integration
+==================
+
+With Nextcloud Hub 26 Winter we introduce a new client integration API. It allows server side apps to expose integrations on Desktop and Mobile.
+For now we support adding app-defined actions to "context menu" of files and folders.
+
+The idea behind it, is to ease the integration of specific actions on clients without the need to write and maintain code on those platforms.
+
+Supported clients
+-----------------
+
+Android: 3.36.0
+Desktop: 4.1.0
+iOS: 7.3.0
+
+Exposing actions via capability
+-------------------------------
+
+Each app can add new actions via capabilities, following the syntax "app-id", "hook-name" and list of all endpoints.
+
+.. code::
+
+    'client_integration' => [
+        Application::APP_ID => [
+            'version' => 0.1,
+			'context-menu' => [
+                … endpoints …
+            ]
+        ]
+    ]
+
+Hooks
+-----
+
+Currently only "context-menu" is supported.
+
+Endpoint
+--------
+The endpoint tells the client how the menu entry should look like and how the client can send a request to the server.
+
+Requirements:
+- Every text need to be translated by the app
+- Current predefined params are fileId and filePath
+- {fileId} and {filePath} will be replaced on clients with actual values
+- url placeholder are always replaced
+- mimetype_filters is a comma-separated list of filters (matches anything that starts with the filter). If there is no filter, the action is shown for every file/folder.
+- all urls must be relative
+- params is used for body params (currently only POST)
+- Icons are always svgs
+- Methoth: supported POST/GET
+
+.. code::
+    [
+        'name' => 'translated title',
+        'url' => '/ocs/v2.php/apps/abc',
+        'method' => 'POST/GET',
+        'mimetype_filters' => 'text/, application/pdf', // will match text/* and PDFs
+        'params' => ['file_id' => '{fileId}','file_path' => '{filePath}'], // only for POST; the key can vary depending on the app
+        'icon' => '/apps/abc/img/app.svg'
+    ],
+
+Response
+--------
+When clicking on a menu entry the client sends a predefined request to the server.
+The app in question can then handle the request and can send two different response types.
+
+Declarative UI
+^^^^^^^^^^^^^^
+
+
+Tooltip Response
+^^^^^^^^^^^^^^^^
+The tooltip response is a regular DataResponse type, with payload:
+- version: Indicates which version it is. Clients will be backward compatible. If server sends a newer version than the client can understand the response will be ignored.
+- tooltip: Translated text, which will be shown as tooltip / snackbar.
+
+.. code::
+    {
+      "ocs": {
+        "meta": {
+          "status": "ok",
+          "statuscode": 200,
+          "message": "OK"
+        },
+        "data": {
+          "version": "0.1",
+          "tooltip": "Task submitted successfully"
+        }
+      }
+    }
+
+Issues/Bugs
+-----------
+
+Please report issues, bugs or feature requests at https://github.com/nextcloud/files-clients with label "Client integration".
+
+
diff --git a/developer_manual/client_apis/index.rst b/developer_manual/client_apis/index.rst
index 95f4ee646fa..b5d94754c3d 100644
--- a/developer_manual/client_apis/index.rst
+++ b/developer_manual/client_apis/index.rst
@@ -15,4 +15,5 @@ Clients and Client APIs
     OCS/index
     RemoteWipe/index
     WebDAV/index
+    ClientIntegration/index