Glossary /Technical SEO
XML Sitemap
A machine-readable list of the URLs on a site that its owner considers worth indexing, used by crawlers as a discovery hint.
An XML sitemap lists the canonical URLs a site wants crawled, usually with a last-modified date. It is a hint rather than an instruction: it helps an engine discover pages that are poorly linked internally, and it tells the engine when something changed, but inclusion does not earn indexing and omission does not prevent it.
Its underrated use is as a diagnostic. Submit a clean sitemap of exactly the pages that should be indexed, then compare that list against what the engine reports as indexed. The gap is a precise list of problems, and it is far more actionable than a coverage report over every URL the crawler has ever seen.
A sitemap should contain only URLs that return 200 and are self-canonical. Listing redirects, noindexed pages or non-canonical variants sends a contradictory signal — the site is nominating pages it has separately told the engine to ignore.