The Stockfish Chess Engine for Flutter.


iOS project must have IPHONEOS_DEPLOYMENT_TARGET >=11.0.


@PScottZero was kind enough to create a working chess game using this package.

Add dependency

Update dependencies section inside pubspec.yaml:

  stockfish: ^1.0.0

Init engine

import 'package:stockfish/stockfish.dart';

# create a new instance
final stockfish = Stockfish();

# state is a ValueListenable<StockfishState>
print(stockfish.state.value); # StockfishState.starting

# the engine takes a few moment to start
await Future.delayed(...)
print(stockfish.state.value); # StockfishState.ready

UCI command

Waits until the state is ready before sending commands.

stockfish.stdin = 'isready';
stockfish.stdin = 'go movetime 3000';
stockfish.stdin = 'go infinite';
stockfish.stdin = 'stop';

Engine output is directed to a Stream<String>, add a listener to process results.

stockfish.stdout.listen((line) {
  # do something useful

Dispose / Hot reload

There are two active isolates when Stockfish engine is running. That interferes with Flutter's hot reload feature so you need to dispose it before attempting to reload.

# sends the UCI quit command
stockfish.stdin = 'quit';

# or even easier...

Note: only one instance can be created at a time. The factory method Stockfish() will return null if it was called when an existing instance is active.