Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work and JS instrumentation
Cost / License
- Free
- Open Source
Application type
Platforms
- Self-Hosted
- Docker
Portugal
EU
Open Source reCAPTCHA AlternativesAnti-Spam Tools and other similar apps like reCAPTCHA
The best open source alternative to reCAPTCHA is Cap Captcha. If that doesn't suit you, our users have ranked more than 25 alternatives to reCAPTCHA and 11 is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to reCAPTCHA are Anubis, Procaptcha, ALTCHA and mosparo.
Alternatives list
58 Anubis alternativesApplies sha256 proof-of-work challenges to incoming HTTP requests, targeting AI crawlers, bots that ignore robots.txt, and automated scrapers, protecting server resources and preventing unwanted search engine indexing for privacy-focused sites.
Cost / License
- Free Personal
- Open Source (MIT)
Application typeApplication types
Platforms
- Self-Hosted
- Go (Programming Language)
- Docker
Canada
Prosopo Procaptcha redefines user verification with a unique approach that emphasizes privacy and security. It's a pioneering solution designed to offer an alternative to conventional CAPTCHA systems that often compromise user privacy.
Cost / License
- Freemium
- Open Source (Apache-2.0)
Application typeApplication types
Platforms
- Online
- Software as a Service (SaaS)
- Wordpress
United Kingdom
+3
26 ALTCHA alternativesALTCHA is a privacy-first solution built to help developers and website owners stop bots, spam, and automated abuse — without making things harder for real users. It replaces traditional CAPTCHA systems with a smarter, quieter approach to verification and threat detection.
Czechia- EU
mosparo is the modern solution for protecting your online forms from spam. The protection method is quite simple: mosparo blocks spam using rules matching the form’s data. The detection method is comparable to an e-mail spam filter.
Switzerland
+9
conCaptcha is a self-hosted captcha which is faster, more user-friendly and more customizable than other captchas - available for PHP and ASP.NET websites. Users no longer have to read any annoying text images, solve difficult math equations or play any puzzle games.
Cost / License
- Free
- Open Source (MIT)
Platforms
- Self-Hosted
Cost / License
- Free
- Open Source
Platforms
- Self-Hosted
Cost / License
- Free
- Open Source
Platforms
- Online
- Self-Hosted
Privacy-first, self-hosted CAPTCHA for the modern web. No Google. No telemetry. No visual puzzles. Protect your software from bots without handing over your users' data to a third party.
Mexico
India
