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
A blazing fast, async-first, undetectable webscraping/web automation framework based on ultrafunkamsterdam/nodriver. Now with Docker support!
The fast and secure Load Balancer / API Gateway / Reverse Proxy with built-in service discovery, GeoIP, WAF, bot protection and much more - https://pingoo.io
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 10 projects tagged captcha, with 49,136 GitHub stars between them. The most-adopted is SafeLine at 23,143 stars.
Are these captcha projects free to use?
Yes — 8 of the 10 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?
8 of the 10 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.