head to head · open source
Cap vs Abby
Cap has 8,236 GitHub stars, 637 forks, 10 open issues and last shipped 5 days ago. Abby has 167 stars, 49 forks, 31 open issues and last shipped 1.3 years ago. Cap leads on adoption by 4,832% (8,236 vs 167 stars). Cap is written in JavaScript under a custom or non-standard licence; Abby is written in TypeScript under AGPL-3.0. Cap has attracted 8% as many forks as stars, Abby 29%. Cap was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | Abby | |
|---|---|---|
| GitHub stars | ★ 8.2K | ★ 167 |
| License | Custom / other | AGPL-3.0 |
| Written in | JavaScript | TypeScript |
| Last push | 2026-10-29 | 2025-07-24 |
| Forks | ⑂ 637 | ⑂ 49 |
| 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 Abby if
- You want the Abby feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches TypeScript
- You evaluated both and Abby 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 Abby
About Abby Abby is a open source feature management and A/B testing platform. It is designed to be easy to use and easy to integrate into your existing applications. It aims to improve the developer experience by providing a simple and statically typed API for feature management and A/B testing. Besides its official SDKS it also offers a friendly and easy to understand Dashboard for the non developers in your team. Abby focuses on privacy. This means it won't track any personalized user data and uses no marketing cookies. You can self host it or use the hosted version available at tryabby.com. Getting Started…
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Frequently asked questions
Is Cap or Abby more popular?
Cap has 8,236 GitHub stars and Abby has 167. Cap has the larger community by that measure.
Are Cap and Abby free?
Both are open source. Cap has no licence declared in this registry, and Abby is licensed under AGPL-3.0. Both are free to self-host.
What is the difference between Cap and Abby?
Cap is written in JavaScript and Abby in TypeScript. 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 Abby?
Choose Cap if you want the larger community (8,236 stars) or its Custom / other licence terms. Choose Abby if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.