Cap

Lisbon, Portugal

Cap is an open-source, self-hosted reCAPTCHA alternative that verifies visitors without visual puzzles, tracking, or third-party services.

It uses a two-layer verification model that combines proof-of-work challenges accelerated with WebAssembly and Web Workers, including SHA-256 hashing and optional GPU-resistant time-locks.

It uses Redis/Valkey for storage and can be deployed with Docker.

💸 Pricing

Cap is available for free.

Free ✔️ Open source

⚡ Sites Using Cap

The list of sites that use Cap is still being compiled.
#WebsiteRankCountryLanguage
1 ipax.at #507,692 Austria German
2 laotradeportal.gov.la #924,318 Laos Lao
3 artsencollectief.nl #1,321,661 Netherlands Dutch
4 envipath.org #1,330,136 Germany English
5 colorker.com #1,499,330 Spain European Spanish
6 bizibaratzea.eus #1,622,353 Spain Basque
7 wimpernwelle.de #4,064,850 Germany English
8 tobrunet.ch Switzerland German
9 grunfy.com Germany English
10 trycap.dev American English

📈 Usage Statistics

Statistics for Cap are still being collected and will be available later.

🕵️ Similar Technologies

These are some of the best Cap alternatives.

RankName
1
reCAPTCHA
Mountain View, California, United States

A Google service that protects websites from spam, fraud, and automated abuse by distinguishing human users from bots.

Free tier$8+/month
2
hCaptcha
San Francisco, California, United States

A security service for detecting and preventing human and automated abuse on websites and applications, often used as a drop-in alternative to reCAPTCHA.

Free$99+/month
3
Cloudflare Turnstile
San Francisco, California, United States

A user-friendly CAPTCHA alternative that verifies human visitors without requiring them to solve interactive puzzles or identify objects.

Free$$$
4
Yandex SmartCaptcha
Moscow, Russia

A captcha and bot protection service from the Russian technology company Yandex.

Free tier$0.80
6
Altcha
Brno, Czech Republic

An open-source, privacy-first, self-hosted captcha alternative that uses a proof-of-work mechanism to protect websites, APIs, and online services from spam and unwanted content.

FreeOpen source€99+/month

🆚 Compare Alternatives

Compare Cap to…

💬 Frequently Asked Questions

Where is Cap's headquarters?

Cap is located in Lisbon, Portugal.

Can I use Cap for free?

Yes, it is a free captcha service.
Moreover, it is an open-source solution and its code can be found on GitHub.

Which country uses Cap the most?

The majority of Cap users are from Germany.

Who uses Cap?

According to our data, Cap is used on at least 10 sites, including such established ones as ipax.at, laotradeportal.gov.la, and artsencollectief.nl.

Is Cap used on government websites?

Yes, for example, it is used by laotradeportal.gov.la.

What are the alternatives to Cap?

Alternatives and possible competitors to Cap may include reCAPTCHA, Altcha, and hCaptcha.

👉 See Also

🗃️ About This Data