A LITTLE KNOW-HOW
Understand the details.
Practical guides to the things our tools check. What the results mean, why they matter, and what to do next.
What an HTML checkup can tell you.
Understand document structure, alternative text, titles, and the limits of automatic checks.
02 / URL HYGIENERedirects and canonicals, explained.
Read an HTTP redirect chain and make sense of a page’s preferred URL.
03 / FIRST IMPRESSIONSMake your links look like your site.
Write useful page titles and descriptions, and add metadata for social sharing.
04 / DOCTOR HTMLDoctor HTML, then and now.
Find current help for old checker links, understand the findings, and explore the original records.
05 / WEB RESOURCESGo to the source.
Official references for HTML, JavaScript, accessibility, HTTP and maintaining server code.
These guides describe the checks in the current toolkit. They are starting points for practical website maintenance; use the linked technical references for the underlying specifications and platform behavior.