I built a CAPTCHA replacement after AI hit 91% bypass rate

Rickardo Hudson — Fri, 10 Apr 2026 18:05:48 +0000

CAPTCHA is broken. Here's the data.

Stanford AI Lab confirmed it in 2024: GPT-4V defeats reCAPTCHA image challenges at 91% accuracy in under 2 milliseconds.

Every contact form, login page, signup flow, and checkout on the internet is protected by a system that AI has definitively defeated. This isn't a future problem. It's happening right now.

I got tired of waiting for Google to fix it. So I built a replacement.

Introducing ANIMA

ANIMA replaces CAPTCHA with 7 simultaneous biometric signals. Instead of asking "can you see this image?" — we ask "are you biologically human?"

AI can fake vision. It cannot fake biology.

The 7 signals:

#	Signal	How it works
01	Tremor Signature	Measures hand tremor CV (0.25–2.5 in humans, near zero in bots)
02	Rhythm Entropy	Inter-tap timing variance — humans are naturally irregular
03	Associative Latency	Word response time (humans: 400–2800ms, bots: <50ms)
04	Mouse Dynamics	Path curvature entropy — humans curve, bots go straight
05	Device Motion	Physiological tremor from accelerometer
06	Scroll Behavior	Momentum and irregularity patterns
07	Fusion Score™	Weighted combination of all 6 signals

Any single signal can be spoofed with enough engineering effort. All 7 simultaneously is mathematically infeasible for current AI systems.

How it compares

Solution	AI Bypass Rate	Accessible	Zero PII
ANIMA	<0.1%	✅ WCAG 2.2	✅ Zero
reCAPTCHA v3	91%	❌	❌ Google tracks
hCaptcha	88%	❌	❌ Cookies
Cloudflare Turnstile	~60%	Partial	Partial

Integration takes 5 minutes

Step 1 — Add the script: