Alternatives to Cap

CAPTCHA	Open-source	Free	Private	Fast to solve	Easy for humans	Small error rate	Checkpoint support	GDPR/CCPA Compliant	Customizable	Hard for bots	Easy to integrate
Cap	✅	✅	✅	✅	✅	✅	✅	✅	✅	🟨	✅
Cloudflare Turnstile	❌	✅	🟨	🟨	✅	❌	🟨	✅	❌	🟨	✅
reCAPTCHA	❌	🟨	❌	✅	❌	🟨	❌	🟨	❌	❌	✅
hCAPTCHA	❌	🟨	🟨	❌	❌	🟨	❌	🟨	❌	🟨	✅
Altcha	✅	✅	✅	🟨	✅	✅	❌	✅	✅	🟨	🟨
FriendlyCaptcha	❌	❌	✅	🟨	✅	✅	❌	✅	✅	🟨	🟨
MTCaptcha	❌	🟨	🟨	❌	❌	🟨	❌	✅	❌	❌	🟨
GeeTest	❌	❌	❌	🟨	🟨	🟨	❌	✅	❌	🟨	🟨
Arkose Labs	❌	❌	❌	❌	❌	❌	❌	✅	🟨	❌	❌

Notes:

• "Hard for bots" does not include solvers like 2captcha or BrightData, as I cannot verify their legitimacy myself.
• Arkose Labs is considered "Easy for Bots" as their audio CAPTCHA is easy to solve by multi-modal LLMs.

All alternatives

Cloudflare Turnstile

Cloudflare Turnstile is a great alternative to Cap, but unfortunately it is known for having an extremely high error rate and relies a lot on fingerprinting, especially for users using private browsers such as Brave or Librewolf. Also, unlike Turnstile, Cap is open-source and self-hosted.

reCAPTCHA

Not only is Cap significantly smaller and faster than reCAPTCHA, it's open-source, fully free and is significantly more private. Cap doesn't require you to check traffic signs or solve puzzles, and it doesn't track users or collect data. reCAPTCHA is also highly inefficient due to its challenges being easily solved by multi-modal LLMs like Gemini 2.5

hCAPTCHA

Pretty much the same as reCAPTCHA, although hCAPTCHA is significantly more secure. Personally it's the best alternative to Cap, even though the widget's bundle size alone is significantly bigger.

Fun fact about hCAPTCHA, an attacker can easily solve it for $1.05/1k results while you (the site owner) need to pay hCAPTCHA $1/1k solves just for the captcha, even if the content behind the captcha doesn't cost you anything.

Imagine if anyone could drain $100 dollars from your bank account just by knowing your name and paying $105 - pretty scary, right?

Altcha

Cap is slightly smaller than altcha and easier to integrate, but if you don't care about that and want a more popular solution I would highly recommend checking it out.

FriendlyCaptcha

Unlike FriendlyCaptcha, Cap is free and open-source (FriendlyCaptcha is €39/month for 5,000 requests and 5 domains) and has a smaller bundle size.

MTCaptcha

Cap is more lightweight, doesn't rely on users solving an image puzzle that LLMs and OCR can easily solve and is open-source and self-hostable.

GeeTest

Cap is free, self-hosted and open-source, while GeeTest is a paid service. Cap is also more private and doesn't rely on tracking users or collecting data. GeeTest is also china-based, which means that it has to hand over data to the chinese government if they request so. Note that GeeTest partially uses MD5 PoW too.

Arkose Labs

Even while being extremely hard, slow and annoying for humans to solve, Arkose's FunCAPTCHA can be easily solved by LLMs due to their audio CAPTCHA. It's also closed-source and paid.