Installation and platform setup

Requirements

Runtime	Minimum
Flutter	3.22
Dart	3.4
Android	API 21
iOS	16
macOS	14
Linux and Windows	Native Flutter build toolchain

Install

flutter pub add kittentts

The package installs flutter_onnxruntime, path_provider, http, archive, and ffi. Do not register flutter_onnxruntime manually unless your application configures it directly.

Flutter Web

Load ONNX Runtime Web before Flutter in web/index.html:

<script src="https://cdn.jsdelivr.net/npm/onnxruntime-web@1.22.0/dist/ort.min.js"></script>
<script src="flutter_bootstrap.js" async></script>

Then run:

flutter run -d chrome

Web model paths resolve to Hugging Face by default. modelFiles may point to asset keys or HTTP URLs. The bundled JS/Emscripten CE runtime handles phonemization because Dart FFI cannot load the native bridge in a browser.

Smoke test

final tts = await KittenTTS.create(
  onProgress: (progress, info) {
    print('${(progress * 100).round()}% ${info?.stage.name}');
  },
);

final result = await tts.generate('Flutter setup is working.');
await tts.dispose();