Free, open-source, 100% offline AI text-to-speech.

A native desktop app for macOS, Windows, and Linux that reads text aloud with natural-sounding voices.
Everything runs locally on your machine. No cloud, no accounts, no telemetry.

Contents

• What it does
• Screenshots
• Install
• Supported languages
• How it works
• API
• Repository layout
• Build from source
• Scripts
• Documentation
• Contributing
• License
• Credits

What it does

• Reads text aloud with 50+ natural voices across 8 languages
• Runs 100% offline. Nothing leaves your computer
• Built on Kokoro-82M, an open-weight TTS model ranked highly on the TTS Arena
• Desktop app with menu-bar / system-tray integration
• Chrome & Safari extensions to read any webpage in one click
• Local HTTP API on port 51730 for extensions and scripts

Screenshots

Install

Grab the latest release for your platform from the Releases page:

• macOS: Out Loud-<version>.dmg (Apple Silicon & Intel)
• Windows: Out Loud-<version>.exe
• Linux: Out Loud-<version>.AppImage

Or build it yourself. See Build from source.

Supported languages

English (US & UK), Japanese, Chinese (Mandarin), Spanish, Brazilian Portuguese, Italian, and Hindi. 50+ voices total.

How it works

The Electron app owns the ONNX model, runs TTS in a worker thread, and exposes a local HTTP API on port 51730 that the browser extensions talk to. Nothing goes to the network.

flowchart LR
  subgraph Desktop["Out Loud desktop app (Electron)"]
    UI[Renderer UI<br/>React + Vite]
    Main[Main process]
    Worker[TTS worker<br/>ONNX + espeak-ng]
    UI <-- IPC --> Main
    Main <-- messages --> Worker
  end

  HTTP[["HTTP :51730"]]
  Main --- HTTP

  Chrome[Chrome extension]
  Safari[Safari extension]
  Scripts[Your scripts / curl]

  Chrome --> HTTP
  Safari --> HTTP
  Scripts --> HTTP

API

The Electron app exposes a local HTTP API on 127.0.0.1:51730. A few quick examples:

# List voices
curl http://127.0.0.1:51730/api/v1/audio/voices

# Generate audio to a file
curl -X POST http://127.0.0.1:51730/api/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{"voice":"af_heart","input":"Hello, world."}' \
  --output hello.wav

Full reference: docs/app/api.md. Machine-readable OpenAPI 3.1 spec: docs/app/openapi.yaml. Also served live at http://127.0.0.1:51730/api/v1/openapi.yaml while the app is running.

Repository layout

.
├── electron/           TTS engine + main process (TypeScript)
├── electron-ui/        Renderer UI (React + Vite + Tailwind)
├── chrome-extension/   Chrome / Chromium extension
├── safari-extension/   Safari extension (generated from chrome-extension)
├── tray-app/           Standalone menu-bar app variant
├── scripts/            Icon generation, dev server helpers
├── build-resources/    Icons, entitlements, DMG background for electron-builder
└── docs/               Deeper docs (app, extensions, build)

Build from source

Prerequisites

• Node.js >= 22 (LTS)
• npm >= 10
• macOS, Windows, or Linux

Install

git clone https://github.com/light-cloud-com/out-loud.git
cd out-loud
npm install
npm run electron-ui:install

Develop

# Electron app + hot-reloaded UI
npm run electron:dev

# Compile only the Electron main process
npm run electron:compile

# Run the UI in a browser (no Electron) for faster iteration
npm run electron:browser

Build distributables

npm run electron:build           # current platform
npm run electron:build:mac       # macOS .dmg
npm run electron:build:win       # Windows .exe
npm run electron:build:linux     # Linux .AppImage

Output lands in releases/<platform>/. See Output layout.

Extensions

npm run extension:chrome:pack    # zip the Chrome extension
npm run extension:safari:convert # convert to Safari (macOS, Xcode required)
npm run extension:test           # smoke-test the local HTTP API

Output layout

All build artifacts land under releases/ (gitignored):

releases/
├── macos/           *.dmg, *-mac.zip
├── windows/         *-Setup.exe
├── linux/           *.AppImage, *.deb
└── extensions/
    ├── out-loud-chrome.zip
    └── safari/      Xcode project (generated)

For automated releases via GitHub Actions, see docs/build/releasing.md.

Scripts

Documentation

Deeper docs live in docs/:

• App: docs/app/architecture.md, docs/app/api.md, docs/app/voices.md, docs/app/openapi.yaml
• Extensions: docs/extensions/testing.md, chrome-extension/README.md, safari-extension/README.md
• Build: docs/build/releasing.md, docs/build/mac-app-store.md
• Contributing: CONTRIBUTING.md

Contributing

Issues, pull requests, translations, and new voices are all welcome. See CONTRIBUTING.md to get started.

License

MIT. See LICENSE.

Bundled third-party components (Kokoro-82M, espeak-ng, onnxruntime-node, Electron, ffmpeg, fonts) retain their own licenses. See THIRD_PARTY_NOTICES.md for the full list.

Credits

• Kokoro-82M, Apache 2.0: TTS model
• espeak-ng: phonemization
• onnxruntime-node: on-device inference

Built by Light Cloud Labs and contributors.