A lightweight, self-hostable, and privacy-respecting captcha solution.

🧠 Invisible Proof-of-Work

Replaces frustrating user puzzles with a quick, background computational challenge that's invisible to humans but effectively deters bots.

🛡️ Self-Hostable & Privacy-First

Host it on your own infrastructure. No user data is ever sent to third-party services, ensuring complete privacy and GDPR/CCPA compliance.

🔒 Advanced Replay Protection

Utilizes time-windowed Redis Bloom filters to efficiently prevent replay attacks, ensuring a solved captcha challenge cannot be reused by an attacker.

📜 Stateless & Secure by Design

Employs modern Ed25519-signed JWTs for challenge tokens. This ensures tamper-proof, stateless communication between your users and the server.

🔌 Drop-in Client Widget

Integrate the captcha into any form with a single script tag and one line of HTML. The widget automatically initializes and handles the entire workflow.

⚖️ Open & Fair Licensing

A permissively licensed client (MIT) allows for easy integration into any project, paired with a copyleft server (AGPLv3) to foster community contributions.