Although it still has not yet issued an API, Google+ appears to be making cautious overtures towards third party developers. The social network has set up a Google+ developer page and has invited those interested to weekly “hangouts.”
According to the site, “Our team will host regular hangouts to talk about the +Platform, your experiences with it, and share tips and tricks with the community. Our weekly office hours hangouts take place every Wednesday at 11:30am — 12:15pm PDT, and can be accessed from our Google+ Developers page. The +Platform team will also share Google+ developer events, conferences and hackathons, as well as photos and videos of the events. In addition, we’ll announce and discuss our +Platform launches on our page.”
So far, the Google+ platform does not appear to have a large community of developers.