Cap is a lightweight, modern open-source CAPTCHA alternative using proof-of-work and instrumentation challenges. It's fast, private, and extremely simple to integrate.
Read the docs, try the demo or read the feature comparison
Cap replaces visual captchas with modern, accessible and privacy-preserving challenges. No images, no tracking, no dependencies, works everywhere.
The default way to use Cap is with the Standalone Docker container. Learn more about how Cap works
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250x smaller than hCaptcha
~20kb, zero dependencies, loads in milliseconds -
Privacy-first
Cap doesn't send any telemetry back to our servers -
Fully customizable
Change the colors, size, position, icons and more with CSS variables -
Proof-of-work
Your users no longer have to waste time solving visual puzzles. -
Standalone mode
Run Cap anywhere with a Docker container with analytics & more -
Programmatic
Hide Cap's widget and solve challenges in the background -
Open-source
Completely free & open-source under the Apache 2.0 license
Cap is a great alternative to reCAPTCHA, hCaptcha and Cloudflare Turnstile
This project is licensed under the Apache-2.0 License, please see the LICENSE file for details.
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