head to head · open source
Cap vs Private Captcha
Cap has 8,236 GitHub stars, 637 forks, 10 open issues and last shipped 5 days ago. Private Captcha has 199 stars, 8 forks, 4 open issues and last shipped 3 days ago. Cap leads on adoption by 4,039% (8,236 vs 199 stars). Cap is written in JavaScript under a custom or non-standard licence; Private Captcha is written in Go under a custom or non-standard licence. Cap has attracted 8% as many forks as stars, Private Captcha 4%. Private Captcha was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 4 topic tags (anti-abuse, anti-bot, captcha, proof-of-work), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Cap | Private Captcha | |
|---|---|---|
| GitHub stars | ★ 8.2K | ★ 199 |
| License | Custom / other | Custom / other |
| Written in | JavaScript | Go |
| Last push | 2026-10-29 | 2026-10-31 |
| Forks | ⑂ 637 | ⑂ 8 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Cap if
- You weight community size — 8.2K stars and counting
- You want the Custom / other license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick Private Captcha if
- You want the Private Captcha feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches Go
- You evaluated both and Private Captcha fits your workflow better
About Cap
Cap Cap is a lightweight, modern open source CAPTCHA alternative using proof of work and instrumentation challenges . It's fast, private, and extremely simple to integrate. Documentation Read the docs , try the demo or deploy on Railway What is Cap? Cap replaces visual captchas with modern, accessible and privacy preserving challenges. No images, no tracking, no dependencies, works everywhere. The default way to use Cap is with the Standalone Docker container. Learn more about how Cap works Why Cap? 250x smaller than hCaptcha 20kb, zero dependencies, loads in milliseconds Privacy first Cap doesn't send any…
About Private Captcha
Private Captcha is an independent, privacy first, self hostable Proof of Work CAPTCHA service made in EU. About Project goals provide powerful means to fight bots, including AI scrapers, and spam even as AI improves make web a slightly better place by replacing existing frustrating CAPTCHAs stay focused on privacy and GDPR compliance as well as on prem deployment provide stable, backward compatible and reliable API and integrations be sustainable financially to fulfill previous goals long enough Features adaptive challenge difficulty (including various configuration options) optimized backend (low resource…
read the full Private Captcha overview →
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Frequently asked questions
Is Cap or Private Captcha more popular?
Cap has 8,236 GitHub stars and Private Captcha has 199. Cap has the larger community by that measure.
Are Cap and Private Captcha free?
Neither Cap nor Private Captcha declares a licence in this registry, so check each project's own repository before relying on either for a commercial use. Both are free to self-host.
What is the difference between Cap and Private Captcha?
Cap is written in JavaScript and Private Captcha in Go. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Cap or Private Captcha?
Choose Cap if you want the larger community (8,236 stars) or its Custom / other licence terms. Choose Private Captcha if its feature set, stack or Custom / other licence fits better. Both are self-hostable.