Stop automated sign-ups without slowing real customers.

OTCaptcha verifies every visitor in the background, raises the cost for suspicious traffic and tightens automatically during an attack.

Join the waitlist See how it works

Sample verificationPassed

Time: 142 ms
Hashes: 65,412
Clicks: 0

Automation flag: Not present
Language: en-US
CPU threads: 8
Touch points: 0

Sample values. Nothing is sent. Run the real check

Protect the pages bots go for first

Sign-up

Keep fake accounts out of your customer base.

Login

Slow down password guessing and stolen-password lists.

Password reset

Stop automated reset requests before they reach your customers.

Any other form

Add the same check wherever automation costs you money.

Three layers, no image puzzles for normal visitors

Layer 1

Proof of work

The visitor's device completes a short calculation. Trivial once, costly at scale.

Layer 2

Risk signals

Automation traces, network origin and inconsistent device details are scored together.

Layer 3

Server verification

Your backend confirms each pass. A pass works once and expires in minutes.

Attack response that runs itself

OTCaptcha learns your usual traffic. When volume or suspicious activity jumps, it steps up protection, then steps back down once the attack ends.

Sign-up attempts during an attackIllustration, not customer data

Normal protectionProtection raised automatically

State	Work per attempt	Suspicious visitors
Normal	1x	Standard checks
Elevated	2x	Held sooner
Severe	4x	Held at the lowest risk score

Built to stay out of your way

Under 10 KB gzipped loader
Host the file yourself or load it from us
Use the latest version or pin an exact one
If our service is down, your sign-ups stay open

Sample integration

// In the browser
const pass = await otcaptcha.check("[SITE KEY]");

// On your server
const valid = await otcaptcha.verify(pass, "[SECRET]");
if (!valid) return rejectSignUp();

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We are onboarding a small number of teams first.