Online-Go.com Developer Resources
gtp2ogs project and documentation
To connect a bot to the online-go.com servers, you’ll need to use the gtp2ogs project which will allow you to connect a bot that speaks the Go Text Protocol to the online-go.com servers.
Realtime API
Playing games, chatting, accessing the AI review system, and many more features relies on establishing a persistent WebSocket connection to the server and exchanging messages.
The protocol is documented in the Goban project here:
GobanSocket Realtime API documentation
REST API
Creating challenges, adding friends, joining tournaments and ladders, loading tsumego, and many more features are done via REST calls to the REST API.
The REST API documentation is a work in progress.