Sitemap validator
Check a sitemap against the spec before a crawler rejects it silently.
Free, no signup, and it runs entirely in your browser.
Sitemap XML
About this tool
The frustrating thing about an invalid sitemap is how it fails. Search Console reports "could not read" without saying which line, so a single unescaped ampersand three thousand URLs down invalidates the whole document and gives you nothing to go on. This checks the specific things the spec requires and names each one.
- The unescaped ampersand is checked first because it is the most common failure and the most destructive: a bare & invalidates the entire file rather than one entry.
- lastmod must be a W3C datetime. "02/09/2026" parses in your head and not in a validator, and the value is ignored rather than reported.
- Every <loc> must be absolute, including the protocol. A relative path is the second most common cause of a rejected sitemap.
- Nothing is fetched — paste the XML. Your sitemap never leaves the browser and no request hits your server.
Questions
- Why does Search Console say my sitemap could not be read?
- Almost always malformed XML — an unescaped ampersand or angle bracket, a missing namespace, or a truncated file. Any of those invalidates the whole document rather than a single entry.
- Is lastmod required?
- No, only <loc> is required. But if you include lastmod it must be a W3C datetime, and it must be true — a value that is always the build time is worse than none.
- What is the sitemap size limit?
- 50,000 URLs or 50MB uncompressed per file, whichever comes first. Past either, split into several files and reference them from a sitemap index.