Scored, not guessed
47 behavioural and network features feed a gradient-boosted model. Every request returns a calibrated 0.00 to 1.00, not a checkbox.
Pro Captcha
Proof of human
Continuous scoring and adaptive proof of work, with a checkbox a script cannot click. Ten lines to integrate. One API to verify.
Why sites move
Work only where needed
Every request pays a quiet proof of work in a worker thread; risky traffic pays up to eight times more. turn sites add one checkbox; scripted clicks fail the score.
Verification you own
Secrets are yours. Tokens are single use, domain bound, and expire in 120 seconds. Hosted score, own backend: your call.
How it works
Three steps, one verdict.
01
Embed
Drop the widget into any form with a sitekey. It solves a quiet proof of work in a worker thread.
02
Score
Behaviour and network signals become a calibrated 0.00 to 1.00. Risky traffic pays more work or sees a checkbox.
03
Verify
Send the single-use token to /v1/siteverify from your backend and act on the score.
Precision
Built like an instrument
A 4.9 kilobyte widget. No frameworks, no fonts, no third-party calls. Ships from the same edge as your page and degrades to a server-side check.
Integration
Two lines in the page.
<script src="https://cdnp.procaptcha.qzz.io/v1/api.js" async defer></script> <div class="procaptcha" data-sitekey="PK_your_sitekey" data-action="signup"></div>
On submit, the widget hands you a token. Verify it server-side with /v1/siteverify. Tokens are single use and expire in 120 seconds, so a replay gets rejected, not scored again.
Operations
Watch it work
Live pass rate, score distribution, risk factors, and p95 challenge latency for every site. Logs are hashed and retention is yours to set.
Ready to stop the bots?
Start on the free tier. Create a site, copy the sitekey, ship.