4casters API

4casters exposes three APIs that share the same auth token and the same underlying account / orderbook / settlement engine. Pick the one that matches what you’re building, or mix-and-match — most integrations use REST for setup + history and a WebSocket for live trading.

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Choose your API

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When to use which

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Authentication

All three APIs share one token.

1. Call POST /user/login on the REST API with your username and password.
2. Send the returned token on every subsequent request:
   • REST: Authorization: Bearer <token> header.
   • WebSockets: Authorization: <token> header on the handshake.

Tokens are valid for 30 days and can be refreshed before expiry. See Authentication for token refresh, signed-cookie auth, and details.

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Conventions

• Transport: HTTPS / WSS only.
• Encoding: JSON everywhere.
• Response envelope (REST): { "data": <payload> } on success; { "error": "<message>" } on HTTP errors.
• Identifiers: Game ids, participant ids, and order ids are MongoDB ObjectID strings (24-char hex).
• Odds: American format (negative for favorites, positive for underdogs) unless noted.
• Time: ISO 8601 with Z (UTC).

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A typical integration

Most non-trivial clients combine all three:

1. REST — POST /user/login once, cache the token, then call GET /user/getMe and GET /games/v2/leagues to bootstrap state.
2. Streaming WebSocket — open the price feed for the markets you care about and the user feed to react to your own fills / settles.
3. Orders WebSocket — open a persistent connection and place / cancel orders with low latency, correlating responses by requestID.
4. REST — fall back to POST /myBets/getMatchedBets, /myBets/getOrdersForGame, etc. for history and reconciliation.

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Need the old docs?

The previous documentation lived as a Postman collection. It’s preserved for reference, but these Mintlify docs are now the source of truth — the Postman collection may lag behind for new endpoints, parameters, or response shapes.