XML sitemap validator: what it checks and how to fix what it finds
Six checks every sitemap should pass before you submit it, and how to run them on seogeoaeo.ai.
By ClaudeGPT Si Newsroom, Editorial team··3 min read
An XML sitemap validator reads your sitemap file and tells you whether a search engine can parse it, and which entries break the rules. The seogeoaeo.ai XML Sitemap Validator does this for one sitemap or sitemap index per run, against both the sitemaps.org protocol and Google's limits.
Search engines treat a sitemap as a hint. A file that fails to parse, or that lists URLs it is not allowed to list, gives them a weaker hint or none at all. Validating before you submit catches those problems while they are cheap to fix.
What a sitemap validator should check
Most sitemap problems fall into a few groups. A useful validator covers each of them.
| Check | The rule | What goes wrong |
|---|---|---|
| Well-formed XML | Every tag closes, special characters are escaped | One stray ampersand stops the whole file from parsing |
| Namespace | The root urlset declares http://www.sitemaps.org/schemas/sitemap/0.9 |
Search Console reports "Incorrect namespace" |
| File size | 50 MB uncompressed at most | Google reports a file size error |
| Entry count | 50,000 URLs per file at most | Google reports "Too many URLs" |
| URL scope | URLs sit at or below the sitemap's folder, on the same host and protocol | URLs on another subdomain or above the folder are not allowed |
| lastmod | W3C Datetime format, such as 2026-10-26 |
Google reports "Invalid date" |
The seogeoaeo.ai validator runs all six. It returns the entry count and lists the URL entries and dates that fail.
How to run it on seogeoaeo.ai
- Find the address of your sitemap. Most sites use
/sitemap.xmlor/sitemap_index.xml, and many name it on aSitemap:line in robots.txt. - Paste the full URL into the tool and sign in. The cost, 10 credits, shows before the run starts.
- Read the result: whether the XML parsed, the namespace, size and count against the limits, then the list of bad URLs and dates.
- If the file is a sitemap index, run the tool again on each child sitemap it lists. The validator checks the file you give it and does not follow the links inside an index.
Developers and AI agents can call the same check over the REST API or MCP with a workspace API key, which suits a pre-deploy step in a build pipeline.
What the validator does not do
Knowing the limits saves a wasted run. The seogeoaeo.ai validator does not discover sitemaps from robots.txt, so you give it the file address. It does not validate image, video or news extension tags. It cannot confirm that Google has read the file; only Search Console's Sitemaps report shows that.
If you need to know whether the pages in your sitemap actually work, the Orphan Page Finder on the same site compares your sitemap with a crawl of your links and flags sitemap URLs that redirect, fail or carry noindex. For a full desktop crawl of a very large site, a dedicated crawler is still the better fit.
Fixing what it finds
Out-of-scope URLs usually mean the sitemap lives in a subfolder or on a different host from its pages. Move it to the site root, or list only URLs from its own host. A file over the limits needs splitting into several sitemaps listed in an index. Bad dates need the generator fixed, not the file, or the error returns on the next build.
Google ignores priority and changefreq, so you can drop them. It uses lastmod only when the dates are consistently accurate, so set it from the date the page content last changed, not the date the sitemap was built.
Validate, then submit
Once the file passes, submit it in Search Console's Sitemaps report or add a Sitemap: line to robots.txt. Then check that report after Google reads it: a "Success" status there, plus a clean validator run, is as close to a guarantee as a sitemap gets.