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.
Online-Go.com REST API documentation
OAuth2 Authentication
For third-party applications that need to authenticate users and access the API on their behalf, OGS provides OAuth2 with PKCE support.