⚡️
250x smaller than hCaptcha
Cap's widget library is extremely small, only 12kb minified and brotli'd.
CapA modern, lightning-quick PoW captcha
Cap is a lightweight, modern open-source CAPTCHA alternative using SHA-256 proof-of-work
Skip to content
🔒️
Private
Cap's usage of proof-of-work eliminates the need for any tracking, fingerprinting or data collection.
🌈
Fully customizable
Cap is self-hostable so you can customize both the backend & frontend — or you can just use CSS variables
🤖
PoW-based
Cap uses proof-of-work instead of complex puzzles, making it easier for humans and harder for bots
🧩
Standalone mode
Cap offers a standalone mode with Docker, allowing you to use it with languages other than JS.
💨
Invisible mode
Cap can run invisibly in the background using a simple JS API.
☁️
Floating mode
Floating mode keeps your CAPTCHA hidden until it's needed
🌳
Fully FOSS
Completely open source under the Apache license 2.0 license