Alternatives to Cap

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

Note

"Hard for bots" for Cap refers to the combination of Proof-of-Work and dynamic instrumentation challenges. It does not consider commercial solvers like BrightData, as I cannot verify their legitimacy myself.

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.

Additionally, unlike Turnstile, Cap is open-source and self-hosted. With Turnstile, if Cloudflare's algorithm marks a user as "suspicious," you cannot override it. Cap puts the levers of control in your hands, so you decide the difficulty and strictness, not a third party.

Full comparison: Cap vs Cloudflare Turnstile →

reCAPTCHA

Not only is Cap significantly smaller and faster than reCAPTCHA, it's open-source, fully free, and much more private. Cap doesn't require you to check traffic signs or solve puzzles, and it doesn't track users or collect data.

reCAPTCHA v2 ("I'm not a robot") is getting harder for humans while remaining trivial for AI solvers (especially audio challenges). v3 (Invisible) is great, but if Google thinks you are "suspicious" (e.g., using a VPN or privacy tools), it often blocks you entirely or forces a hard puzzle loop with no way out.

Full comparison: Cap vs reCAPTCHA →

hCAPTCHA

Pretty much the same as reCAPTCHA, however, while it's significantly more resistant to bots, it imposes a heavy "Puzzle Tax" on your users.

Users hate puzzles. They leave. Drop-off rates on hCaptcha challenges can be 5-15% depending on difficulty. Additionally, hCaptcha's free tier is aggressive with serving puzzles to save their own costs, which hurts your conversion rates.

Full comparison: Cap vs hCaptcha →

Altcha

Cap is slightly smaller than Altcha and includes extra features like progress tracking, instrumentation challenges, and a simpler dashboard. If you don't need these, Altcha is still a solid choice.

Full comparison: Cap vs Altcha →

mCAPTCHA

While mCAPTCHA is similar to both Cap and Altcha, it seems to have been deprecated and has a significantly larger widget bundle.

FriendlyCaptcha

Unlike FriendlyCaptcha, Cap is completely free and self-hosted at any volume (FriendlyCaptcha's Starter plan is €9/month for 1,000 requests/month, with higher tiers as you scale).

Full comparison: Cap vs FriendlyCaptcha →

MTCaptcha

MTCaptcha relies heavily on image challenges, which are usually easily solvable by LLMs and OCRs and have high drop-off rates. Cap is also lightweight, self-hostable and doesn't rely on obfuscation.

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 may be a concern for some users regarding data sovereignty.

Arkose Labs

Arkose's CAPTCHA is known for being hard, slow, and annoying for humans to solve. It is also a paid, closed-source service mostly available to big enterprises.

They also only operate in the US, Canada, Argentina, India, Israel and a small set of other countries, excluding many EU countries.

Anubis

While Anubis is a great scraper deterrent and uses the same proof-of-work concept as Cap, it uses a low difficulty by default (which is easier for bots to solve) and does not provide a standalone CAPTCHA server.

Cap also implements dynamic instrumentation challenges, which make it harder for bots to finish the process after solving PoW.

Full comparison: Cap vs Anubis →