SitemapScan Blog
Compressed .xml.gz Sitemaps: How to Audit Them Without Guessing
A .xml.gz sitemap can be a normal URL set, a sitemap index, or a child sitemap inside a larger collection. The file extension alone tells you almost nothing. Here is how to audit compressed sitemaps correctly.
What a .xml.gz sitemap actually means
The .gz extension only tells you the file is compressed. It does not tell you whether the XML inside is a URL set or a sitemap index. Many large sites compress their sitemap files for efficiency, which means your audit has to inspect the XML root element after decompression.
Why compressed files cause false assumptions
People often treat a compressed sitemap as a special or secondary file just because it looks more technical. In practice, the real coordinating sitemap index may be compressed, or a compressed file may be just one child sitemap among many. The extension is not the deciding signal.
How to classify a compressed sitemap correctly
Fetch the file, decompress it, and inspect the XML root. If the root is <sitemapindex>, the file coordinates child sitemaps. If the root is <urlset>, it is a leaf URL inventory. That is the only reliable way to label it.
About this article
This article is part of the SitemapScan blog and covers XML sitemap, robots.txt, crawlability, or related technical SEO topics.
FAQ
Does a .xml.gz sitemap mean it is a sitemap index?
No. The .gz extension only means the file is compressed. The XML root element is what tells you whether it is an index or a URL set.
Should compressed sitemaps be audited differently?
They should be decompressed and then audited like any other sitemap for XML validity, type, reachability, and structure.
Related pages
- Sitemap Index vs URL Set: How to Tell the Difference and Why It Matters — A sitemap index and a sitemap URL set are not interchangeable. Knowing which one you're looking at changes how you audit coverage, child sitemaps, and the overall structure of a site's crawl map.
- Multiple Sitemaps in robots.txt: What It Means and How to Audit It — Some sites declare one sitemap in robots.txt. Others declare twenty. Here's what multiple sitemap directives actually mean, when they're valid, and how to audit them without missing the real sitemap structure.
- Common Sitemap Validation Errors and How to Fix Them — Even small errors in your sitemap can cause search engines to skip it entirely. Here are the most common validation issues we detect — and exactly how to resolve each one.
- XML Sitemap Checker — Validate the topic against a live sitemap.
- Latest Sitemap Checks — See how similar sitemap patterns show up in the public archive.