Capcat,
the invisible open-source CAPTCHA
No Google, no ad tracking, no image puzzles. Proof of work runs silently in the browser — sign up and protect your forms and APIs in 5 minutes.
Try a different site style:
Give it a click — this talks to the real production service. Switch the style and the widget adapts on its own.
Why Capcat
Verification,
without giving up privacy
Single-use computational proofs are the default. Optional Account Defense processes bounded, signed security aggregates without uploading raw trajectories or building advertising or cross-site profiles.
01/Data minimizationThe widget uses no advertising cookies and creates no cross-site identity. When risk evaluation is enabled, collection is capped at 15 seconds and 128 samples; raw coordinates and event sequences never leave the browser.
02/Invisible to usersUsers just tick a checkbox while a SHA-256 proof of work completes silently in the background — no more squinting at traffic lights and crosswalks.
03/Fully hostedNothing to deploy or operate: create a site in the console to get your keys, global edge nodes respond nearby, and domain binding plus usage dashboards work out of the box.
04/reCAPTCHA-compatibleThe siteverify endpoint is compatible with the reCAPTCHA / hCaptcha API — migrate by changing one URL on the server and swapping in the Capcat widget on the frontend.