diff --git a/api-test/frontend/src/business/commons/json-schema/convert/convert.js b/api-test/frontend/src/business/commons/json-schema/convert/convert.js
index 38f7df463f..ae4ba3ef3f 100644
--- a/api-test/frontend/src/business/commons/json-schema/convert/convert.js
+++ b/api-test/frontend/src/business/commons/json-schema/convert/convert.js
@@ -231,7 +231,7 @@ class Convert {
     } else if (isString(value)) {
       objectTemplate.type = "string";
     } else if (isNull(value)) {
-      objectTemplate.type = "null";
+      objectTemplate.type = "string";
     } else if (isArray(value)) {
       objectTemplate.type = "array";
       objectTemplate["mock"] = undefined;