Cap
by Cap · Self-hosted, open-source CAPTCHA with no visual puzzles
28.8 — BenchRank score out of 100
Screenshots of Cap
Homepage
Overview
Cap is a self-hosted CAPTCHA that replaces reCAPTCHA, hCaptcha or Turnstile. Each verification runs two layers at once: proof-of-work using SHA-256 and time-lock challenges in WASM, and a freshly generated JavaScript program that checks the browser environment through DOM and canvas operations. The widget is about 20 kB, shows no visual puzzles and sends no data to third parties.
- Best for
- Teams replacing reCAPTCHA who want bot protection running on their own servers
- Pricing
- No prices are published: Cap is Apache 2.0 licensed and self-hosted with no quotas or per-request fees, and the site says Cap Standalone fits on a $5 VPS for most sites.
- Runs on
- Self-hosted
Strengths and trade-offs
Strengths
- Apache 2.0 licensed and runs entirely on your own server
- ~20 kB widget, zero dependencies, no third-party scripts
- Invisible checks: proof-of-work plus JS instrumentation
- siteverify API is compatible with reCAPTCHA and hCaptcha
Trade-offs
- No hosted option — you run, update and monitor the server yourself
- Migration needs client-side code swapped, not just the API endpoint
- Challenges rely on WASM and JavaScript running in the visitor's browser
- Compliance list is the vendor's own; the site states it is not legal advice
How this score is made up
Each dimension is scored out of 100 and combined into the headline score using fixed weights.
- MCP support
- 0 out of 100
- API quality
- 0 out of 100
- Documentation
- 0 out of 100
- Agent friendliness
- 100 out of 100
- Changelog
- 100 out of 100
- Marketing site structure
- 35 out of 100
- Operational trust
- 15 out of 100
Measured, but not part of the score
Useful to know, but not a mark for or against the product — so these do not affect the ranking.
- Openness
- 30 out of 100
- Maintenance
- 100 out of 100
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