diff --git a/restapi/index.php b/restapi/index.php
index 41113eb88..158285b6a 100644
--- a/restapi/index.php
+++ b/restapi/index.php
@@ -1322,6 +1322,39 @@ class RestapiController { /* {{{ */
         }
     } /* }}} */
 
+    function addDocumentCategory($request, $response, $args) { /* {{{ */
+        $dms = $this->container->dms;
+        $userobj = $this->container->userobj;
+
+        if(!$userobj) {
+            return $response->withJson(array('success'=>false, 'message'=>'Not logged in', 'data'=>''), 403);
+        }
+
+        if(!ctype_digit($args['id']) || $args['id'] == 0) {
+            return $response->withJson(array('success'=>false, 'message'=>'No document given', 'data'=>''), 400);
+            return;
+        }
+        if(!ctype_digit($args['catid']) || $args['catid'] == 0) {
+            return $response->withJson(array('success'=>false, 'message'=>'No category given', 'data'=>''), 400);
+            return;
+        }
+        $cat = $dms->getDocumentCategory($args['catid']);
+        $doc = $dms->getDocument($args['id']);
+        if($doc && $cat) {
+            if($doc->getAccessMode($userobj, 'addDocumentCategory') >= M_READ) {
+                if ($doc->addCategories([$cat])){
+                    return $response->withJson(array('success'=>true, 'message'=>'', 'data'=>''), 201);
+                } else {
+                        return $response->withJson(array('success'=>false, 'message'=>'Could not add document category', 'data'=>''), 500);
+                }
+            } else {
+                return $response->withJson(array('success'=>false, 'message'=>'No access on document', 'data'=>''), 403);
+            }
+        } else {
+            return $response->withJson(array('success'=>false, 'message'=>'Could not find category or document', 'data'=>''), 500);
+        }
+    } /* }}} */
+
     function removeDocumentCategory($request, $response, $args) { /* {{{ */
         $dms = $this->container->dms;
         $userobj = $this->container->userobj;
@@ -2355,6 +2388,7 @@ $app->get('/document/{id}/attributes', \RestapiController::class.':getDocumentAt
 $app->get('/document/{id}/preview/{version}/{width}', \RestapiController::class.':getDocumentPreview');
 $app->delete('/document/{id}/categories', \RestapiController::class.':removeDocumentCategories');
 $app->delete('/document/{id}/category/{catid}', \RestapiController::class.':removeDocumentCategory');
+$app->post('/document/{id}/category/{catid}', \RestapiController::class.':addDocumentCategory');
 $app->put('/account/fullname', \RestapiController::class.':setFullName');
 $app->put('/account/email', \RestapiController::class.':setEmail');
 $app->get('/account/documents/locked', \RestapiController::class.':getLockedDocuments');