Apps with 'Proof Of Work' feature

Lightweight, modern open-source CAPTCHA alternative designed using SHA-256 proof-of-work and JS instrumentation

Anubis weighs the soul of your connection using a sha256 proof-of-work challenge in order to protect upstream resources from AI scraper bots.

Prosopo Procaptcha redefines user verification with a unique approach that emphasizes privacy and security. It's a pioneering solution designed to offer an alternative to conventional CAPTCHA systems that often compromise user privacy.

A no-nonsense CAPTCHA system with seamless UX | Backend component.

Friendly Captcha is an invisible CAPTCHA and bot protection solution that helps block bots and spam with privacy-first proof-of-work-without image or audio puzzles, cookies, or user tracking. GDPR- and CCPA-compliant and TÜV-certified as conformant with WCAG 2.

TrustCaptcha is a privacy-first, invisible CAPTCHA that protects your website from bots and spam—without disrupting your users.

End-to-end encrypted, read-once notes. AES-256-GCM in the browser, proof-of-work spam protection, zero accounts. Self-hostable, with Rust backend.

Primecoin is an innovative cryptocurrency, a form of digital currency secured by cryptography and issued through a decentralized mining market. Derived from Satoshi Nakamoto’s Bitcoin, Primecoin introduces an unique form of proof-of-work based on prime numbers.

Prove a real, unique human performed an action; mint a signed, verifiable Proof-of-Human credential. MCP server for agents.

Privacy-first, self-hosted CAPTCHA for the modern web. No Google. No telemetry. No visual puzzles. Protect your software from bots without handing over your users' data to a third party.

Hashiverse — your open-source decentralized X/Twitter replacement.