reCAPTCHA is not available as a self-hosted solution but there are plenty of alternatives for power users and business that want to host a solution on-premise. The best Self-Hosted alternative is Cap Captcha, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to reCAPTCHA and 12 are available as a self-hosted solution so hopefully you can find a suitable replacement. Other interesting Self-Hosted alternatives to reCAPTCHA are Anubis, ALTCHA, mCaptcha and Private Captcha.
Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work.
Cap Captcha is the most popular Self-Hosted alternative to reCAPTCHA.
Cap Captcha is the most popular Open Source & free alternative to reCAPTCHA.
Applies 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.
I put this on my company page and now my colleagues think I'm into furries
ALTCHA 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.
Its proof of work only - this is a delay mechanism only so I don't know why its in the "stop bots" category?
It is Free and Open Source. Inspectable.
Private Captcha is an independent, privacy-first, self-hostable Proof-of-Work CAPTCHA service made in EU. Instead of asking users to solve complex puzzles or track their behavior, Private Captcha solves an invisible cryptographic task in the background.
It's the only one that has solid backend code (frontend parts all have the same)
It has many pre-built integrations
GDPR-complisnt and self-hosted.
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.
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.
UniqPin is a free for non-commercial use service which destiny improve ability of interfaces detect a human or a computer operate with it.
It is not a captcha functionality.
It is not a captcha functionality
Portugal
EU
Canada
Czechia
India
Estonia
Switzerland
I tried cap captcha on my site and the bots just kept on spamming me.