Powered by Stockfish 17 lite NNUE. Free API access is available; paid subscriptions are not enabled.
Engine versions
Pin a version with "engine": "stockfish-17" or follow latest. Deprecated versions keep working for six months with Deprecation and Sunset headers. The same list is at GET /v1/engines.
| Version | Stockfish | Net | Released | Status |
|---|---|---|---|---|
stockfish-17 (latest) | 17 | Stockfish.js lite NNUE | 2024-09-06 | current |
Options
| Option | Type | Default | Range | What it does |
|---|---|---|---|---|
hash_mb | int | 8 | 1 to 16 | Transposition table size. Larger helps deep searches; capped by Worker memory. |
limit_strength | bool | false | Play at a target Elo instead of full strength (set `elo`). | |
elo | int | 1320 | 1320 to 3190 | Target Elo when `limit_strength` is true. |
skill_level | int | 20 | 0 to 20 | Coarser strength dial (20 = full strength). Prefer `elo`. |
chess960 | bool | false | Interpret the FEN as Chess960 (castling rights by rook file). | |
show_wdl | bool | true | Include win/draw/loss probabilities in each PV. | |
move_overhead_ms | int | 10 | 0 to 5000 | Only affects `movetime_ms` searches. |
Not exposed, on purpose: Threads (a property of where the engine runs), SyzygyPath (tablebases are a later product), Ponder (meaningless in request-response).