Cap
by Cap · Self-hosted, open-source CAPTCHA with no visual puzzles
BenchRank score
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 Cap markets itself
A structured read of the promise, proof and page design on Cap’s captured homepage.
Homepage capture
“Self-hosted CAPTCHA”
- Angle: Contrarian / anti-incumbent
- Hero: 3D render
Pricing
Published plans and prices from Cap’s own pricing page.
How this score is made up
Each dimension is scored out of 100 and combined into the headline score using fixed weights.
MCP support
Whether an agent can drive the product through the Model Context Protocol, and how much setup that takes.
API quality
Public API surface: machine-readable spec, official SDKs, documented auth, errors, rate limits and versioning.
Documentation
Publicly reachable docs — coverage, freshness, code samples and machine readability.
Agent friendliness
How readable the site is to an automated client: llms.txt, structured data, server-rendered content, crawler access.
Changelog
A public, dated record of what shipped and when — the clearest signal that a product is still alive.
Marketing site structure
Whether the site answers a buyer's questions: clear positioning, the pages that matter, and accessibility.
Page speed
How fast the site loads for real visitors: Chrome UX Report 75th-percentile LCP, INP and CLS, with a Lighthouse mobile run standing in where a site has too little traffic for field data.
Operational trust
Status page and incident history, security disclosure, compliance and data-processing documentation.
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
Source availability, self-hosting, data export and open standards. Scored and shown, but not part of the composite — paid SaaS is not worse for being paid SaaS.
Maintenance
Release cadence and repository activity. Scored and shown, but not part of the composite — it is only measurable for open repositories.
Where this comes from
The Cap pages BenchRank reads when it scores the product — its documentation, release notes, status and security pages, and its repository where there is one.
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Is this your product?
Claim Cap to manage its profile. Claiming lets you suggest edits to the descriptive fields — it never changes scores or rankings.