Open source captcha projects
Every project in the registry tagged captcha, ranked by real GitHub adoption.
SafeLine is a self-hosted WAF(Web Application Firewall) / reverse proxy to protect your web apps from attacks and exploits.
Captcha solver extension for humans, available for Chrome, Edge and Firefox
Privacy-first CAPTCHA alternative with proof-of-work
Next-Gen CAPTCHA and Spam Protection, GDPR compliant
Privacy-first proof-of-work CAPTCHA without user friction
Decentralized CAPTCHA for enhanced web security
GDPR-compliant bot protection without user friction
Invisible bot protection that respects user privacy
Related tags
Frequently asked questions
How many open source captcha projects are there?
This registry tracks 8 projects tagged captcha, with 45,481 GitHub stars between them. The most-adopted is SafeLine at 22,606 stars.
Are these captcha projects free to use?
Yes — 6 of the 8 carry an explicit open-source licence across 5 distinct licences, so there is no licence fee. Where a project also sells a hosted or enterprise version, the self-hosted path remains free.
Which captcha project should I choose?
The list above is ranked by GitHub stars, but stars measure attention rather than fit. Check three things on each card: the licence (permissive versus copyleft), the language it is written in, and the last-push date — a high-star project that has not been pushed in a year is a liability.
Are these captcha projects still maintained?
7 of the 8 were pushed in the last 90 days, and every card shows its exact last-push date so you can see the rest. Sort your shortlist by that date before committing to a migration.