Either update the existing form object to support JSON only data storage, or create an alternate form type/object that stores data as text only. Get away from the strongly typed fields so you don't get type errors in the client. Enable Domino to create a new doc from a JSON string and automatically create the fields and name them based upon the JSON provided. Enable the Notes client to dynamically display the JSON type docs without having a form defined. This would allow you to create an NSF that would be used as a data store for non Notes/Domino applications. Create the NSF and supply the client with CRUD URLs and you're done.