Observed arrival · 2026-09-21
402registry checks whether AI agents can actually see your site
A pay-per-check audit fetches a website like an AI crawler and reports what appears without JavaScript, including bot access, sitemaps, and soft-404 behavior.
- For
- Developers checking crawler visibility and AI discoverability
- Worth noticing
- The audit uses plain HTTP requests and probes robots.txt, sitemaps, soft 404s, and duplicate hostnames.
Field notes
The service models a crawler visit as a plain HTTP exchange rather than a browser session, checking the page body alongside robots.txt, sitemaps, and selected soft-404 paths. Its homepage reports findings from 104 AI-built sites, including duplicate bare and www hostnames and pages that return 200 OK despite not existing. Checks are priced in USDC on Base through x402, with public JSON endpoints for documentation, manifests, reports, and badges.
Observed signals
Read the marks
Editorial observations of this landing page, not a rating.
One card from the complete issue