Listen to the web.
Your way.

A free, open-source Firefox extension that reads any webpage aloud with premium AI voices and real-time word-level highlighting.

Install Free for Firefox View Pricing
example.com/article

The Future of Web Reading

Technology has transformed how we consume information. With advances in artificial intelligence and text-to-speech, listening to the web feels natural.

Open Source (AGPL-3.0) Privacy First 2,800+ Tests Built with TypeScript Firefox 112+

Everything you need to listen to the web

Premium voices, real-time highlighting, and total privacy — no compromises.

Premium AI Voices

Choose from OpenAI, ElevenLabs, Groq, Cartesia, or your browser's built-in voices. Bring your own API key or use managed credits.

Word-Level Highlighting

Follow along as Proso highlights each word in real-time. Never lose your place, even on long articles.

Smart Text Extraction

Automatically detects article content, strips ads and navigation clutter. Or select exactly what you want to hear.

Privacy by Design

API keys stored locally in your browser. No telemetry, no tracking, no data collection. Open-source code you can audit.

Up and running in seconds

Three steps to transform any webpage into an audio experience.

1

Install the Extension

One click from Firefox. No account needed, no signup forms. The free tier works immediately.

2

Navigate to Any Page

Open any article, blog post, documentation, or webpage. Click the Proso icon in your toolbar.

3

Listen

Text is read aloud with word-level highlighting. Control speed, skip paragraphs, and follow along visually.

Simple, transparent pricing

The free tier is genuinely useful — not a crippled trial. Pay only if you want premium voices.

Monthly Annual (Save ~33%)
Free
$0 $0 /forever
  • Unlimited browser TTS
  • Word-level highlighting
  • BYOK — all providers
  • Smart text extraction
  • Managed credits
  • MP3 export
Install Now
Basic
$4.99 $3.33 /month /mo (billed $39.99/yr)
  • Everything in Free
  • 100K chars/month credits
  • OpenAI voices included
  • MP3 export
  • Cloud sync
  • PDF reading
Coming Soon
Pro
$14.99 $9.99 /month /mo (billed $119.99/yr)
  • Everything in Basic
  • 300K chars/month credits
  • OpenAI voices included
  • MP3 export
  • Cloud sync
  • PDF reading
Coming Soon
Multilingual
$19.99 $13.33 /month /mo (billed $159.99/yr)
  • Everything in Pro
  • 300K chars/month credits
  • Google Cloud voices (40+ langs)
  • MP3 export
  • Cloud sync
  • PDF reading
Coming Soon

Bring Your Own Key (BYOK)

Already have an OpenAI, ElevenLabs, Groq, or Cartesia API key? Use premium voices for free on any tier — including Free. No managed credits needed. Your keys, your usage, your control.

How Proso compares

An honest look at how we stack up against the alternatives.

Feature Proso Speechify NaturalReader
Free tier Unlimited browser TTS Limited Limited
BYOK support ✓ All tiers ✗ No ✗ No
Open source ✓ AGPL-3.0 ✗ No ✗ No
Word-level sync ✓ Free Basic free, advanced paid Available (paywall unclear)
Starting price $0 $139/yr $119/yr
Privacy ✓ No data collection Cloud processing Cloud processing
Firefox support ✓ First-class extension Web app only Web app only

Built in the open

Proso is free and open-source software licensed under AGPL-3.0. The entire codebase is auditable, and contributions are welcome.

TypeScript NestJS WXT Framework Playwright Prisma Firefox Extension

Need a commercial license? Proso offers dual licensing for businesses that need terms beyond AGPL-3.0.

Commercial Licensing