Sitemap Validator: Check Your XML Sitemap for Errors
Submitting an invalid sitemap to Google is worse than not submitting one — it creates errors in Search Console, wastes crawl budget on malformed entries, and delays indexing for your most important pages. Validation catches format errors, URL issues, and canonical conflicts before Google sees them.
Why Sitemap Validation Matters
An invalid sitemap can cause Google to reject it entirely, preventing your pages from being discovered. Validation ensures your sitemap follows the XML Sitemap Protocol that Google, Bing, and other search engines rely on. SitemapFixer's sitemap checker validates XML structure, checks every URL for 200 status, and flags canonical mismatches — free, no account required.
The XML Sitemap Protocol Requirements
A valid sitemap must use the correct namespace: xmlns="http://www.sitemaps.org/schemas/sitemap/0.9". Each URL entry must be wrapped in url tags containing at least one loc tag with an absolute URL.
Common Validation Errors
The most common errors are: missing or incorrect namespace declaration, special characters not encoded such as ampersand, missing closing tags, URLs not absolute, mixed HTTP and HTTPS URLs, and incorrect date format in lastmod which must be ISO 8601 YYYY-MM-DD.
How to Validate Your Sitemap
Enter your sitemap URL into SitemapFixer. The tool checks XML syntax, verifies the namespace, validates URL format, checks all URLs are accessible, and flags protocol or canonical mismatches.
Validating Sitemap Index Files
If your site has a sitemap index file referencing multiple child sitemaps, validate both the index file and each child sitemap. The index must use the sitemapindex namespace and reference each child sitemap with a sitemap loc tag.
After Validation: Submit to Google
Once your sitemap passes validation, submit it in Google Search Console. Go to Sitemaps in the left menu, enter your sitemap URL, and click Submit. Monitor the report over the following days to confirm Google processes it without errors.
Validating lastmod Date Format
The lastmod element must follow ISO 8601 format: either YYYY-MM-DD (e.g., 2026-04-27) or the full datetime format YYYY-MM-DDThh:mm:ss+TZ. Many CMS plugins generate invalid lastmod dates — for example, using a human-readable date like "April 27, 2026" which fails XML validation. A validator that checks date format catches these silently malformed entries that Google ignores without reporting an error. Inaccurate lastmod values (dates that don't reflect actual content changes) also reduce trust: Google learns to ignore lastmod signals from sites that update the date without changing content.
Beyond XML Validity: Checking URL Health
An XML-valid sitemap can still contain URLs that harm your indexing. A thorough sitemap validation checks each URL's HTTP status code: URLs returning 301 redirects waste crawl budget and should be replaced with the final destination URL. URLs returning 404 errors waste crawl budget and create Search Console errors. URLs returning 5xx server errors signal instability to Googlebot. URLs behind authentication return 401 or 403, which Google cannot crawl. Remove or fix any URL not returning a clean 200 status before submitting your sitemap.
Canonical Alignment Check
Every URL in your sitemap should have a self-referencing canonical tag — a canonical that points to itself. If a page's canonical tag points to a different URL, Google will index the canonical target instead of the submitted URL. This creates the "Submitted URL not selected as canonical" warning in Search Console. A good sitemap validator checks canonical alignment for every URL: if the submitted URL and the canonical on that page don't match, it flags the mismatch so you can either update the canonical or remove the URL from your sitemap.
How SitemapFixer Validates Sitemaps
SitemapFixer goes beyond basic XML validation. It fetches your sitemap, parses every URL, sends HTTP requests to check status codes, reads canonical tags on each page, checks robots.txt for conflicts, and identifies noindex pages that conflict with sitemap inclusion. The result is a prioritized issue list with specific fixes for each problem — not just a pass/fail XML check. Run it before submitting to Search Console to catch issues that would otherwise appear as mysterious Coverage errors weeks later.
When to Re-run a Sitemap Validation
Validate your sitemap after any significant site change: publishing new content batches, deleting or redirecting pages, changing URL structures, upgrading your CMS or sitemap plugin, or migrating to a new domain. Also re-validate if Google Search Console reports new sitemap errors or if your indexed page count drops unexpectedly. A monthly validation check is a reasonable baseline for sites that publish content regularly — catching sitemap issues early prevents weeks of lost indexing time.