Build on the engine.

1. Create a key

Open Settings → API keys, create a key and copy it once. Keys start with cu_ and can be revoked at any time.

2. Send a position

curl https://chessurge.org/api/engine/analyse \
  -H "Authorization: Bearer cu_your_key" \
  -H "Content-Type: application/json" \
  -d '{"fen":"rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1","nodes":10000000,"multipv":3}'

nodes is capped at 500,000,000 per request. multipv is 1–5. 200,000,000 nodes cost one credit.

3. Stream an infinite search

POST /api/engine/stream
Authorization: Bearer cu_your_key
Content-Type: application/json

{"fen":"...","multipv":3}

The response is text/event-stream. Events are info, final, balance, done and error. Close the connection to stop the search and refund unused nodes.

Endpoints

• GET /api/engine/me — account and balances.
• POST /api/engine/analyse — bounded search.
• POST /api/engine/stream — infinite stream with a node cap.

Limits: 60 requests/minute and 30 streams/minute per account. Illegal FENs and unsupported API keys return 400/401.

Desktop engine

Prefer a native UCI engine? Download the Windows build from Downloads; it uses the same API key and shows your live balance.