Cap is a fast, lightweight, and privacy-first alternative to traditional CAPTCHAs. Instead of relying on tracking or intrusive user puzzles, Cap uses SHA-256 proof-of-work (PoW) to verify requests. At just ~20kb (including WASM), it’s about 250x smaller than hCaptcha—making it ideal for modern apps, APIs, and forms that need security without bloat.
Privacy and customization are at the core of Cap. No fingerprinting, no data collection—just clean, transparent verification. Cap is fully open-source under the Apache 2.0 license and self-hostable, so you can run it on your own infrastructure, customize the frontend and backend, or simply tweak CSS variables for seamless integration with your design.
Built for developers who care about speed and user experience. Cap can run invisibly in the background, float when needed, or even serve as a lightweight Cloudflare-style checkpoint with just two lines of code. With standalone Docker mode and multi-language support, Cap is the simplest, most flexible way to stop spam and abuse—without sacrificing privacy or performance.
