Because the official tools are limited, dedicated developers have built their own:
Older versions had GET /rooms/list. Current game obtains room lists via getroomlist internal message. transformice api
If you want to experiment with the Transformice Lua API: Because the official tools are limited, dedicated developers
Unlike the in-game Lua API, the external API requires authentication for actions like sending whispers or changing room settings. You need a transformice_session cookie and an api_token. These can only be obtained via OAuth2 through Atelier 801's SSO (Single Sign-On), which requires user consent. If you want to experiment with the Transformice
Note: Atelier 801 strictly prohibits automated accounts (bots) playing the game. However, read-only stat fetching is generally tolerated.