diff --git a/README_JSON_API.md b/README_JSON_API.md
index 6a62cf88..3052b8de 100644
--- a/README_JSON_API.md
+++ b/README_JSON_API.md
@@ -583,8 +583,11 @@ POST /api/queue/items/add
 | Parameter       | Value                                                       |
 | --------------- | ----------------------------------------------------------- |
 | uris            | Comma seperated list of resource identifiers (`track`, `playlist`, `artist` or `album` object `uri`) |
+| expression      | A smart playlist query expression identifying the tracks that will be added to the queue.                |
 | position        | *(Optional)* If a position is given, new items are inserted starting from this position into the queue.  |
 
+Either the `uris` or the `expression` parameter must be set. If both are set the `uris` parameter takes presedence and the `expression` parameter will be ignored.
+
 **Response**
 
 On success returns the HTTP `200 OK` success status response code.
@@ -596,6 +599,8 @@ On success returns the HTTP `200 OK` success status response code.
 
 **Example**
 
+Add new items by uri:
+
 ```shell
 curl -X POST "http://localhost:3689/api/queue/items/add?uris=library:playlist:68,library:artist:2932599850102967727"
 ```
@@ -606,6 +611,18 @@ curl -X POST "http://localhost:3689/api/queue/items/add?uris=library:playlist:68
 }
 ```
 
+Add new items by query language:
+
+```shell
+curl -X POST "http://localhost:3689/api/queue/items/add?expression=media_kind+is+music"
+```
+
+```json
+{
+  "count": 42
+}
+```
+
 
 ### Moving a queue item