Cap (CAPTCHA)
lastmod 2025-05-30created 2025-05-301 edits
A lightweight, PoW-based open-source CAPTCHA replacement.
Features
- An open-source CAPTCHA alternative based on SHA-256 Proof-Of-Work, faster and more privacy-friendly than existing CAPTCHAs and very simple to integrate
- 250 times smaller than hCaptcha, privacy-focused, and works without tracking user information or collecting fingerprints
- JavaScript-based, so it can be integrated into any JS runtime (Bun/Node.js/Deno), and can also run standalone with a REST API via Docker
- Easy to customize and self-host; the backend and frontend can be freely modified, or the look adjusted with CSS alone
- The proof-of-work approach makes blocking bots easy, and it offers various modes such as invisible/floating that appear only when needed