7 open-source Captcha & Bot Detection vendors
Open-source software for Captcha & Bot Detection that you can self-host, with auditable source code — regardless of the developer's headquarters.
- vendors scored
- 7
- European
- 4
- last checked
- 11 October 2026
Vendors, scored
Score per vendor: 0 = high exposure, 100 = sovereign
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- Sovereignty score 94 out of 100ALTCHACzechia · Self-hosted / open sourceCzech open-source proof-of-work captcha alternative
- Sovereignty score 94 out of 100CaptchaService (Stad München)Germany · Self-hosted / open sourceOpen-source framework by the City of Munich's IT department (it-at-m) wrapping ALTCHA in a secure, multi-tenant Spring Boot microservice for government portals.
- Sovereignty score 94 out of 100Gregwar Captcha BundleFrance · Self-hosted / open sourceWidely-used, open-source web-rendering library (Symfony bundle) that generates inline image captchas on your own application server. Created by Grégoire Passault (Bordeaux, France); no controlling company.
- Sovereignty score 94 out of 100mosparoSwitzerland · Self-hosted / open sourceOpen-source alternative to traditional captchas that checks form data in real time for suspicious patterns and spam traits, without tracking or external API calls. Maintained by the non-profit mosparo Association (Mellingen, Switzerland).
- Sovereignty score 79 out of 100mCaptchaIndia · Self-hosted / open sourcePowerful open-source, standalone Proof-of-Work verification system (AGPL licence) with a full admin panel to dynamically adjust difficulty per form. Created by Aravinth Manivannan (India); no controlling company.
- Sovereignty score 79 out of 100Swetrix CAPTCHAUnited Kingdom · Non-EU vendorPrivacy-first, open-source proof-of-work verification tool (npm package @swetrix/captcha) by Swetrix Ltd, integrating seamlessly with their sovereign web-analytics platform. Registered in Edinburgh, UK; data hosted in the EU.
- Sovereignty score 77 out of 100AnubisCanada · Self-hosted / open sourceOpen-source web firewall (MIT licence) from Techaro, Canada, that blocks scraper bots with challenges in front of web applications; self-hosted.
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