BuddyPress.org

Of course there’s a BuddyPress “API”. How do you think we write plugins and themes that rely on BuddyPress? If you are specifically talking about stuff like how WordPress can use XML-RPC for remote blog posts, then, no, there’s nothing like that at the moment. You could use the AJAX functions for quite a lot of stuff, however.

I would imagine this is a very low priority feature suggestion and such a thing would more likely be driven by someone writing some kind of external app.