diff --git a/rest-api-spec/api/search.json b/rest-api-spec/api/search.json
index 9ed58293712..af778d5ef58 100644
--- a/rest-api-spec/api/search.json
+++ b/rest-api-spec/api/search.json
@@ -8,6 +8,7 @@
       "parts": {
         "index": {
          "type" : "list",
+         "default" : "_all",
          "description" : "A comma-separated list of index names to search; use `_all` or empty string to perform the operation on all indices"
         },
         "type": {