Most API resources have a field where you can attach arbitrary data. We refer to this arbitrary data as “user data,” and you can access it via the user_data parameter.

User data is useful for storing additional, structured data along side an API object. For example, you may wish to store an ID or key that correlates an API object with a unique ID in your own application or database. User data is not used by Manifest and won’t be visible to your users (unless you expose it to them in your own application).

You may pass any arbitrary JSON object for userdata. The total size of the object, serialized, must be less than 1KB in size.