Im trying to add messaging to a platform I'm building with a friend, this looks like a good potential fit. Im currently using Twilio IP Messaging, but the fact

Im trying to add messaging to a platform I'm building with a friend, this looks like a good potential fit. Im currently using Twilio IP Messaging, but the fact I need to implement the UI and doesn't supports attachements/pictures is aslo not great. Anyone has tried other good alternatives? One of our main requirement is that we keep control of who can be added to a contact list based on a transaction.