head to head · open source
Cap vs ALTCHA
Cap has 7,798 GitHub stars, 579 forks, 10 open issues and last shipped 2 days ago. ALTCHA has 2,757 stars, 132 forks, 0 open issues and last shipped 7 days ago. Cap leads on adoption by 183% (7,798 vs 2,757 stars). Cap is written in JavaScript under a custom or non-standard licence; ALTCHA is written in TypeScript under MIT. Cap has attracted 7% as many forks as stars, ALTCHA 5%. Cap was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 5 topic tags (anti-abuse, anti-bot, antispam, captcha), 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 | ALTCHA | |
|---|---|---|
| GitHub stars | ★ 7.8K | ★ 2.8K |
| License | Custom / other | MIT |
| Written in | JavaScript | TypeScript |
| Last push | 2026-09-16 | 2026-09-11 |
| Forks | ⑂ 579 | ⑂ 132 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Cap if
- You weight community size — 7.8K 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 ALTCHA if
- You want the ALTCHA feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and ALTCHA fits your workflow better
About Cap
Cap is a free, open source, self hosted CAPTCHA replacement that swaps visual puzzles for proof of work and instrumentation challenges, built for developers and site operators who want anti bot protection without shipping their visitors' data to a third party service.
About ALTCHA
ALTCHA is self hosted privacy first security tool. It lives in TypeScript open source web component ecosystem. It belongs to application security. It protects websites, APIs, and online services from spam, bots, and abuse. It uses proof of work mechanism instead of traditional visual puzzles. It is MIT licensed. Operators run it on own infrastructure.
read the full ALTCHA overview →
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Frequently asked questions
Is Cap or ALTCHA more popular?
Cap has 7,798 GitHub stars and ALTCHA has 2,757. Cap has the larger community by that measure.
Are Cap and ALTCHA free?
Both are open source. Cap has no licence declared in this registry, and ALTCHA is licensed under MIT. Both are free to self-host.
What is the difference between Cap and ALTCHA?
Cap is written in JavaScript and ALTCHA 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 ALTCHA?
Choose Cap if you want the larger community (7,798 stars) or its Custom / other licence terms. Choose ALTCHA if its feature set, stack or MIT licence fits better. Both are self-hostable.