API reference
7 checks, explained
The published checker explainers — what each one verifies and what a failure looks like.
Updated 2026-11-12
Checker reference
One page per published checker explainer — what it checks, what a failure looks like, and how to fix it.
- Favicon checker
Show the right icon next to every search result.
- Article structured-data checker
Qualify for article rich results with valid typed markup.
- Breadcrumb structured-data checker
Show a clean breadcrumb trail under the search result.
- Hreflang checker
Send each language version to the right searchers.
- Preferred sources checker
Make clear which page is the original.
- Site name checker
Show one consistent site name across every result.
- AI crawler policy checker
Stay citable when AI answers pick their sources.