Simple, transparent pricing
The free tier is genuinely useful — unlimited browser TTS with BYOK support. Pay only when you want managed premium voices.
- Unlimited browser TTS
- Word-level highlighting
- BYOK — all providers
- Smart text extraction
- Speed control
- Paragraph navigation
- Managed credits
- MP3 export
- Cloud sync
- Everything in Free
- 100K chars/month credits
- OpenAI voices included
- Priority support
- MP3 export
- Cloud sync
- PDF reading
- Everything in Basic
- 300K chars/month credits
- OpenAI voices included
- MP3 export
- Cloud sync
- PDF reading
- Credit rollover (up to 100K)
- Everything in Pro
- 300K chars/month credits
- Google Cloud voices (40+ langs)
- MP3 export
- Cloud sync
- PDF reading
- Credit rollover (up to 100K)
Enterprise
Need a commercial license, custom integration, or white-label solution? We offer flexible licensing for businesses of all sizes.
Contact UsBring Your Own Key (BYOK)
Already have API keys from a TTS provider? Use them with Proso for free on any tier — including the Free plan. Your keys stay in your browser. Proso never sees them.
- OpenAI — High-quality voices with natural intonation
- ElevenLabs — Ultra-realistic AI voices with word timing
- Groq — Blazing-fast inference at low cost
- Cartesia — Low-latency streaming voices
Frequently Asked Questions
What happens when I run out of credits?
Your extension automatically falls back to your browser's built-in text-to-speech engine, which is always unlimited and free. You can also use your own API keys (BYOK) to access premium voices without spending credits.
Can I use my own API keys?
Yes, on every tier — including Free — and it's always free. Bring your own OpenAI, ElevenLabs, Groq, or Cartesia API key and use premium voices without spending any managed credits. Your keys are stored locally in your browser and never sent to Proso servers.
Is there a free trial?
The Free tier is unlimited forever — it's not a trial. You get unlimited browser TTS, word-level highlighting, and BYOK support permanently. Paid tiers include a 7-day free trial so you can try managed credits and premium features risk-free.
What's your refund policy?
Full refund within 7 days for annual plans, no questions asked. Monthly plans are prorated — you'll receive a refund for the unused portion of your billing period.
Do unused credits roll over?
Pro and Multilingual tiers allow up to 100,000 characters to roll over to the next billing period. Basic tier credits reset each month. Credits never expire mid-billing cycle.