What rich results are
Rich results are search results with extras: star ratings and prices for products, dates for events, a video thumbnail, a breadcrumb trail instead of a long address. Google builds them from structured data (schema.org markup) on the page.
This checker reads the page's JSON-LD, matches each item to the rich result it can unlock, and checks the properties Google requires. Items with every required property are eligible. Items missing something are listed with the exact fix.
Eligible doesn't mean guaranteed
Valid markup makes a page eligible, but Google decides case by case whether to show a rich result, based on the search, the device and the quality of the page. The markup also has to describe what's actually visible on the page.
Rich results Google no longer shows
Google has retired several rich results: How-to (2023), fact checks, vehicle listings, estimated salaries and special announcements (2025), and FAQ results (May 7, 2026). Old markup for these does no harm, and this tool marks it as retired so you don't spend time on it.