Sitemap Validator Tool Build

I built the Sitemap Validator to answer the question many XML validators skip: not just whether a sitemap exists, but whether it is helping search engines discover the right URLs.

A sitemap can be valid XML and still be bad SEO. It can list redirected URLs, blocked URLs, noindex pages, canonical variants, or stale pages that no longer belong in search discovery.

Direct sitemap URLs and homepage-based sitemap discovery

robots.txt sitemap declarations

XML sitemap vs sitemap index structure

URL counts and key sitemap fields

Sampled URL HTTP status and redirects

robots.txt conflicts

noindex tags

canonical mismatches

The public tool page runs in Astro, while the validation work happens through a Cloudflare Worker. Users can paste a sitemap URL or a homepage URL. If they start from a homepage, the Worker checks robots.txt first, then falls back to the common /sitemap.xml path.

The validator samples listed URLs instead of pretending every sitemap needs a slow full crawl. That keeps the tool fast for a first-pass audit while still catching the patterns that usually explain sitemap quality problems.

The results are organized by severity so the report points users toward the issues most likely to waste crawl attention or send mixed search signals.

The tool turns sitemap QA into a repeatable workflow: find the sitemap, identify the structure, sample the listed URLs, and connect XML health with crawl/index signals.

Paired with the robots.txt checker and indexability checker, it forms a practical crawl-discovery suite for technical SEO audits.