Replace / Google reCAPTCHA
Best free Google reCAPTCHA alternatives (open source, self-hosted) 2026
The best open-source alternative to Google reCAPTCHA is ALTCHA or mCaptcha, self-hosted on Railway. A CAPTCHA you host. ALTCHA is MIT proof-of-work; mCaptcha is AGPL-3.0 — Google reCAPTCHA without the third-party widget.
Estimated save $1,200 a year.
Open the stackStart on Railway
How Google reCAPTCHA compares
| Google reCAPTCHA | ALTCHA / mCaptcha | |
|---|---|---|
| Pricing model | Hosted subscription | Open-source or fair-code license; you pay the host |
| Hosting | Vendor cloud | Self-hosted on Railway or any VPS |
| Rough monthly cost | Public list price not verified this run | Hosting only — no SaaS seat meter in this repo |
- ALTCHA
MIT self-hosted proof-of-work CAPTCHA
- mCaptcha
AGPL-3.0 proof-of-work CAPTCHA backend if you want that stack
FAQ
- What is the best free open-source Google reCAPTCHA alternative?
- The best open-source alternative to Google reCAPTCHA is ALTCHA or mCaptcha, self-hosted on Railway. A CAPTCHA you host. ALTCHA is MIT proof-of-work; mCaptcha is AGPL-3.0 — Google reCAPTCHA without the third-party widget.
- Is it free?
- The ALTCHA / mCaptcha licenses are open source or fair-code. You still pay hosting (Railway or any VPS) and any APIs the stack calls. There is no Google reCAPTCHA seat or task bill on this path.
- Can I migrate from Google reCAPTCHA?
- Yes. Start with the workflows or data you actually use, then cut over. The ALTCHA / mCaptcha stack page has the agent prompt and the cost table; most teams rebuild the slice that matters and leave old Google reCAPTCHA links until they expire.
- How do I deploy it?
- Open the ALTCHA / mCaptcha stack, copy the agent prompt, and deploy on Railway (one service, PORT, and a volume when the app needs disk). Placeholder: ALTCHA ships as a widget plus optional server checks; mCaptcha is a self-hosted backend. Bind HTTP to 0.0.0.0:$PORT. No one-click template in this repo yet — Start on Railway. Auth stays on /stacks/auth-without-the-bill.
- What does this replace?
- Google reCAPTCHA. The published small-team estimate on this stack is $1,200 a year.
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