LectionFree Tool

Sitemap Checker

Validate sitemap discovery, XML health, child sitemap links, duplicate URLs, and lastmod coverage before you crawl or audit a site.

Free sitemap checkerSitemap health auditrobots.txt sitemap discovery
Free to runNo credit cardStructured results
Enter a homepage to discover sitemap files automatically, or paste a direct sitemap XML URL when you want to validate a specific file.
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This checker reads sitemap declarations from robots.txt, falls back to common sitemap paths when needed, and audits a few child sitemaps for real issues.

What is a sitemap checker?

A sitemap checker validates whether a site publishes usable XML sitemap files and whether those files send clean crawl signals. That is different from a simple sitemap viewer. A viewer shows URLs. A checker confirms how the sitemap was discovered, whether the XML loads correctly, whether a sitemap index points to valid child files, and whether the URLs inside look healthy enough for search engines or scraping workflows.

This matters because sitemap problems are often quiet failures. A site may declare the wrong sitemap in robots.txt, ship duplicate URLs after a migration, mix domains unintentionally, or omit lastmod fields that your crawl prioritization depends on. A fast sitemap health check helps you catch those issues before you hand the URL list to an SEO team, a crawler, or a no-code extraction workflow.

For Lection users, a clean sitemap is also a strong starting point for structured scraping. When the sitemap is healthy, you can move from discovery into extraction with a much more reliable list of pages, product URLs, or content clusters.

How to use a sitemap checker

Step 1

Start with the domain

Paste the homepage when you want the tool to discover sitemap files from robots.txt or standard paths like /sitemap.xml.

Step 2

Read the discovery source

If the checker found the sitemap through robots.txt, that is usually the cleanest signal. If it fell back to standard paths, confirm robots.txt is not missing a declaration.

Step 3

Review health signals

Focus on XML load status, child sitemap counts, duplicate URLs, off-host URLs, and lastmod coverage before you export the data or launch a crawl.

Example: if a sitemap index loads with 12 child sitemaps but one child file returns an error, that usually points to a partial deployment or stale robots declaration. Fix the broken child first, then rerun the check before you trust the sitemap for indexing or extraction.

Another common pattern is a healthy URL count with weak freshness metadata. If the checker shows 0% or low lastmod coverage, the sitemap can still be useful, but you lose an important signal for incremental crawls, recrawl priority, and content monitoring.

Common use cases

  • Validate sitemap files before a site migration, domain consolidation, or CMS change.
  • Confirm that robots.txt points to the intended sitemap index and not an outdated file.
  • Check whether a sitemap is clean enough to seed a crawl or no-code scraping workflow.
  • Spot duplicate or off-host URLs that may confuse SEO audits or internal reporting.
  • Review lastmod coverage before building recurring monitoring jobs or delta crawls.
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Frequently asked questions

What does a free sitemap checker actually validate?
This sitemap checker validates how sitemap files are discovered, whether the XML loads, whether a sitemap is a urlset or index, whether child sitemap links look valid, and whether common quality signals like duplicate URLs, off-host URLs, and lastmod coverage need review.
What is the difference between a sitemap checker and a sitemap viewer?
A sitemap viewer is mostly for browsing URLs. A sitemap checker adds health validation. It helps you answer whether the sitemap declaration is correct, whether the file structure is valid, and whether the URL data is clean enough to trust.
Why would a sitemap checker warn about off-host URLs?
Off-host URLs are not always wrong, but they often deserve a second look. They can appear during migrations, CDN setups, multilingual site rollouts, or accidental cross-domain mixing. The warning is there so you confirm the pattern is intentional.
Can I use this sitemap checker before scraping a site?
Yes. It is a practical first step before scraping because it tells you whether the sitemap is a reliable source of seed URLs. If the sitemap is healthy, you can export the findings and use the URL structure to plan a cleaner extraction workflow.
Why is missing lastmod coverage important in a sitemap audit?
The lastmod field helps search teams and crawlers understand what changed recently. When that field is mostly missing, you can still use the sitemap, but it becomes harder to prioritize recrawls, content freshness checks, and incremental extraction jobs.
What should I do if robots.txt does not declare a sitemap?
First confirm whether the site intentionally relies on a standard path like /sitemap.xml. If that path works, consider adding a Sitemap directive to robots.txt anyway because it improves discoverability for crawlers and auditing tools.

Related resources

XML Sitemap Viewer

Open a sitemap file, browse the listed URLs, and export the results.

Open tool →

Robots.txt Analyzer

Inspect crawler directives and sitemap declarations from robots.txt.

Open tool →

Link Extractor

Compare sitemap URLs with the links actually present on a page.

Open tool →

Complete Guide to robots.txt

Learn how robots directives and sitemap declarations work together.

Open tool →

Lection Home

Turn healthy sitemaps and page lists into reusable extraction workflows.

Open tool →

If you want to go one step further after the audit, use the sitemap output as a seed list for a structured crawl, then move into page-level checks like canonicals, headings, metadata, and link extraction.

Explore Lection pricing if you need recurring runs, exports, and browser-based extraction after the sitemap audit is complete.