diff --git a/rest-api-spec/api/indices.validate_query.json b/rest-api-spec/api/indices.validate_query.json
index 468dd7e1917..a761ca3f7fd 100644
--- a/rest-api-spec/api/indices.validate_query.json
+++ b/rest-api-spec/api/indices.validate_query.json
@@ -32,6 +32,10 @@
         "source": {
           "type" : "string",
           "description" : "The URL-encoded query definition (instead of using the request body)"
+        },
+        "q": {
+          "type" : "string",
+          "description" : "Query in the Lucene query string syntax"
         }
       }
     },