Facebook Chat limitations
My company develop a product for customer support on Facebook and we want to give the representatives a way to contact the customer via Facebook Chat. I have read the Chat API documentations and it is not clear whether users MUST be friends on Facebook in order to chat or is it just enough they both installed a Facebook app? more limitations? any insight will be appreciated.
Thanks in advance for you answers, Yaniv Hakim
Facebook provides an XMPP port to the outside world while internally it implements MQTT. As per XMPP specs, messaging works between two entities without they being in each other roster list (friend/contact list). However, Facebook seems to have this limitation as part of their own business requirement. I think even GoogleTalk disallows this if two federated entities try to send message to each other without being on the roster list.
In short, yes you can just send the message. You don't need a presence authorization from someone in order to send messages to them (in XMPP world). HOWEVER, some services has a policy of requiring this, despite the fact that this is not mandated by the XMPP specifications.