Update custom metadata (like external_URI) for a specific external user or globally.
Custom JSON metadata. Useful for storing external system references (e.g., {'internal_app_ref': 'REF-123'}). This metadata is scoped: updates here apply only to the specified external_user_id (or globally if omitted). When fetching, specific user metadata overrides global metadata.
The external user ID to update. If omitted, updates the global access rule. Note: If the document was uploaded/scoped to a specific user, you must provide that ID here to update their specific metadata.
Successful Response