402registry

Check whether AI crawlers (GPTBot, ClaudeBot, PerplexityBot) see a website: free lookup of dated verdicts; new checks paid with x402 on Base.

View on 402registry.comTry this MCPSponsored

Hosted MCP Server

npx add-mcp 'https://402registry.com/mcp'

Installs into Claude Code, Codex, Cursor and more

Documentation

GET / HTTP/1.1
Host: example.com
User-Agent: GPTBot/1.0
Accept: text/html

<html>
  <head></head>
  <body>
    <div id="app"></div>
    <script src="app.js"></script>
  </body>
</html>

What we actually measured

We checked 104 live sites built by AI coding agents with a plain HTTP request — no browser, no JavaScript, exactly what an AI crawler does when it visits a page.

  • 61% empty shell without JavaScriptunder 300 characters of visible text
  • 67% return 200 OK for a page that does not exist(soft 404)
  • 40% serve www and the bare domain as duplicatesno redirect
  • 12% have a dead www or a dead bare domain

None of it looks broken to a human in a browser. It is invisible to a crawler that never runs JavaScript — and the site has no way to know that happened.

How it works

  1. 1 Pay per check. $0.10 for one check over the x402 protocol — USDC on Base, no account, no card, no human on either side.
  2. 2 We fetch your site as a bot. The same request an AI crawler makes: no JavaScript, a self-identifying user agent, robots.txt, sitemap, the page itself, and a few soft-404 probes.
  3. 3 You get a report with evidence. Every finding quotes what we actually saw, not an opinion, plus a fix for your specific stack.
  4. 4 A passing check earns a badge and a listing — free. You pay for the analysis, not for the listing: a site that fails pays the same and is not listed, and nothing about a failure is ever published. Dated, machine-verifiable, free to look up at /api/check. Opt out with ?catalog=no.

Pricing

  • One check1 check$0.10$0.10/check

Add your site — free

Ask for a free check. If your site passes, it gets a listing in the catalog with a description and a real link. Being queued is not a promise of listing: only sites that pass are listed, and the queue is processed slowly.

Don't want to be listed? Disallow 402registry-check in your robots.txt or write to abuse@402registry.com. We honour both, and we never list a site that has opted out.

For AI agents

Everything below is a plain GET request. No API key beyond the x402 payment itself. The one exception is POST /submit, which is free and takes {"host":"example.com"}.

Manifest

https://402registry.com/.well-known/402registry.json

OpenAPI

https://402registry.com/openapi.json

Docs (JSON)

https://402registry.com/docs

Buy a check

https://402registry.com/buy/{pack}?site={url}

Free lookup

https://402registry.com/api/check?url={url}

Badge

https://402registry.com/badge/{host}.svg