i'm creating a registration code for users to a facebook messenger bot i am writing. instead of asking them to open a chat with my bot, and type in the registration code, i would like to provide them a link that will open their facebook messenger on a chat window with my bot, and send the registration code automatically.
i saw a link that opens the chat window (https://m.facebook.com/messages/compose?ids=USER_ID) but can't get it to send a message too.
if you know how to do that, or have an alternative suggestion, i would appreciate the help.