diff --git a/compose/config/config_schema_v3.0.json b/compose/config/config_schema_v3.0.json
index 584b6ef5..fbcd8bb8 100644
--- a/compose/config/config_schema_v3.0.json
+++ b/compose/config/config_schema_v3.0.json
@@ -308,6 +308,7 @@
           },
           "additionalProperties": false
         },
+        "internal": {"type": "boolean"},
         "labels": {"$ref": "#/definitions/list_or_dict"}
       },
       "additionalProperties": false