diff --git a/schemas/rum/_common-schema.json b/schemas/rum/_common-schema.json
index be0319c2..2a0fa609 100644
--- a/schemas/rum/_common-schema.json
+++ b/schemas/rum/_common-schema.json
@@ -244,6 +244,7 @@
       "type": "object",
       "description": "Synthetics properties",
       "required": ["test_id", "result_id"],
+      "additionalProperties": true,
       "properties": {
         "test_id": {
           "type": "string",