XML sitemap validator

What an XML sitemap is for

An XML sitemap is a list of the addresses you want a search engine to know about. It does not make pages rank and it is not a substitute for links — a page nothing links to is still an orphan — but it is how a search engine finds out quickly that something exists, and it is the cheapest file on the whole site to get right.

What this validator does

It reads robots.txt first, because a Sitemap: line beats guessing, then fetches what it finds and parses it the way a search engine would. It reports what is there, what is broken, and whether anything is over Google's published limits.

The faults worth knowing about

• 50,000 addresses or 50MB per file. That limit is per file, not per site. Past it, use a sitemap index that points at several smaller files.
• A file that answers 200 and parses to nothing. This is the one most tools get wrong, including an earlier version of ours: a broken sitemap reported as a missing sitemap sends you looking for the wrong problem entirely.
• Addresses on another domain. A sitemap may only list addresses on its own site.
• Listing pages that redirect, 404 or carry noindex. It is a list of what you want indexed, so every entry should be a page that can be.
• Never declared. One Sitemap: line in robots.txt is read by every search engine, with no account anywhere.

Next: how to run a full SEO audit, or test what robots.txt allows.