Cap
Cap offers an open-source, self-hosted CAPTCHA alternative using proof-of-work and instrumentation challenges.
About Cap
Cap is a self-hosted, privacy-first CAPTCHA alternative that verifies visitors without traffic-light puzzles, tracking, or third parties watching visitors. The browser quietly solves small background challenges to distinguish humans from bots, scrapers and unwanted automated traffic. Operators host and maintain their own instance.
Pricing is not clearly stated.
Key features
- GPU-resistant proof-of-work and instrumentation challenges
- No dependencies by default
- Runs with Docker, on Workers or on Railway
- Licensed under Apache 2.0
- Used in production by bunny.net and AdGuard
Cap at a glance
- Website
- github.com/tiagozip/cap
- Category
- Privacy & Security › Security Tools
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Details verified
- Oct 22, 2026 · Official source
- Open source
- Yes · Source code
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
Guides for Security Tools
Cap alternatives
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