Title and description truncation is measured in real pixels from the bundled font metrics, the way search results and social cards actually cut text — not by counting characters.
fetched, not parsed
Icons are decoded to their real pixels, hreflang alternates are fetched to confirm their return links, and robots.txt is evaluated with Google’s own matching rules.
dated specs
Every rule that depends on a platform’s behavior shows the date it was last checked against that platform’s documentation, so you can judge how fresh it is.
self-audited
Every page here passes every one of its own checks, and a test fails the build if one stops doing so — the report linked above is this site grading itself.
CLI & API
The same engines answer as JSON, keyless and free, for CI, scripts and editors: