# Step 3. Validate and troubleshoot custom visual transforms in AWS Glue Studio
<a name="custom-visual-transform-validation"></a>

 AWS Glue Studio validates the JSON config file before custom visual transforms are loaded into AWS Glue Studio. Validation includes: 
+  Presence of required fields 
+  JSON format validation 
+  Incorrect or invalid parameters 
+  Presence of both the .py and .json files in the same Amazon S3 path 
+  Matching filenames for the .py and .json 

 If validation succeeds, the transform is listed in the list of available **Actions** in the visual editor. If a custom icon has been provided, it should be visible beside the **Action**. 

 If validation fails, AWS Glue Studio does not load the custom visual transform.