CAPTCHAs in the age of AI agents: a neutral, living guide
How CAPTCHAs work, how AI agents fare against them, which one fits your site, and measured data from real widgets. No vendor money, no third-party scripts.
Facts on this page checked 2026-11-01
CAPTCHArena explains human checks on the web from both sides: for the people who run sites and for the people who build AI agents. Every fact carries the date it was checked and a link to its source. We sell nothing, take no vendor money and run no third-party scripts.
The state of CAPTCHAs, November 2026
| Finding | Evidence (checked 2026-11-01) |
|---|---|
| Most checks now happen before any puzzle. The site scores the session and shows a puzzle only when unsure. | Turnstile asks for a click only "if a further check is necessary"; hCaptcha Pro defaults to "99.9% Passive". |
| Visible picture puzzles no longer stop capable models. | Free local models passed 92.6% of 500 real reCAPTCHA image sessions; the authors say such CAPTCHAs "may have reached the end of their useful life". |
| New "AI-proof" puzzle designs tend to fall within months. | Agents passed 40% of Open CaptchaWorld in May 2025 (paper); nine months later the same group reported up to 90% on its hardest type (Next-Gen CAPTCHAs). |
| Human solving farms remain the cheap baseline. | Token services return reCAPTCHA v2 and Turnstile passes in 4–13 s for $0.0006–0.003 each (Broken Gates). |
| What lasts is cost, scarce human-bound resources and accountability. | Signed agents (Web Bot Auth), rate-limited anonymous credentials (Privacy Pass ARC draft), and pricing abuse above what it earns (Motoyama et al.). |
Details and more sources: How AI agents fare against CAPTCHAs and What still works.
Latest results from the measurement page
First results after the 7-day warm-up, ~2026-11-10. Our domain is new, and Google warns that reCAPTCHA scores in a site's first week may differ from later ones, so nothing is published before the warm-up ends. When the measurement service publishes its summary, this box fills in by itself from https://measure.captcharena.org/api/summary.
What is on this site
| Section | What it gives you |
|---|---|
| Learn | How CAPTCHAs work, every major vendor and open option, the history, the economics, how agents fare, a fake-CAPTCHA safety guide, a glossary. |
| Play | Real CAPTCHA widgets on our own domain with the vendor's live verdict; practice puzzles are coming. |
| Scoreboard | How we measure agents, solvers and widgets, and the live results once the warm-up ends. |
| Browser score | The invisible score sites give your browser, what each vendor weighs, and a live check of your own browser. |
| Defend | A neutral chooser for site owners, defence recipes per threat, fact sheets, accessibility, attacker cost. |
| Build | For agent developers: signing, hand-off to the human, the policy and legal map, test pages that still work. |
| Research | The literature map, industry roadmap, benchmarks and datasets, the half-life measure, open questions. |
How this site stays honest
- Neutral. No vendor money, no affiliate links, no ads. Recommendations come with their trade-offs. Our policy.
- Dated. Vendors change their products and terms every few months, so every fact shows when we checked it.
- Measured. Our own numbers come from real widgets on our own domain, checked by each vendor's own server, never from puzzle answers we grade ourselves. Method.
- Safe. We never sell CAPTCHA solving, and our practice puzzles never imitate a vendor's look. A real CAPTCHA never asks you to press keys, paste a command or download anything: spot a fake one.