OfflineTTS

Overview

OfflineTTS is a Chrome extension that converts web pages, selected text, and PDFs to speech using Supertonic’s neural TTS technology. It operates entirely offline and locally, ensuring complete privacy while delivering high-quality audio output.

Key Features

Voice Options

• Male Voice 1
• Male Voice 2
• Female Voice 1
• Female Voice 2

All voices use neural TTS technology for natural-sounding speech.

Content Support

• Read entire web pages
• Read selected text snippets
• Read PDF documents
• Automatic article text extraction

Playback Controls

• Speed adjustment (0.5x to 2.0x)
• Pause and resume functionality
• Skip forward and backward
• Real-time synthesis

Keyboard Shortcuts

• Alt+P - Play/Pause
• Alt+O - Stop
• Alt+. - Skip forward
• Alt+, - Skip backward

Privacy First

OfflineTTS processes all speech synthesis locally on your device. No data is sent to external servers, ensuring complete privacy for your browsing and reading activities.

Technical Details

Technology Stack

• TTS Engine: ONNX Runtime Web with WASM backend
• PDF Processing: PDF.js library
• Build System: Webpack
• Processing: CPU-based local synthesis

Language Support

• English
• Korean

Installation

From Chrome Web Store

Install directly from the Chrome Web Store.

Local Installation

For users who prefer to bypass Google’s distribution:

git clone https://github.com/hkdb/offline-tts
cd offline-tts
npm install
npm run build

Then load the dist folder as an unpacked extension in Chrome.

Current Limitations

• WebGPU acceleration not yet implemented (work in progress)
• Relatively large file size due to local processing models
• Limited to English and Korean languages

Version

Current version: v0.01.0

License

Licensed under Apache 2.0

Credits

Built with assistance from Claude OPUS 4.5 and Sonnet 4.5 through OpenCode.