Sitemap Index Validator Online Free
Drop the sitemap index plus every child file at once and get one merged audit: duplicate locations, strict lastmod checks, loc linting and per file lastmod patterns.
Index and all children together, .xml or .xml.gz
Or paste XML
Loaded documents (0)
- No sitemaps loaded yet.
Audit report
- .gz files are unpacked with the browser native gzip stream.
- XML parsing and every lint rule run in this tab.
- Child coverage is matched by file name, no network fetch needed.
- Nothing is stored, logged or emailed.
How to Validate a Sitemap Index and All Its Children
A broken sitemap index silently drops whole sections of a site from crawling. This runs the full stack locally:
- Drop everything at once - The index file and every child sitemap it points to, including .xml.gz archives. The list on the right shows each document with its type and entry count.
- Read the merged counters - Documents audited, child sitemaps declared by the index, how many of them you actually provided, total URLs, duplicate locations, invalid and future lastmod values, oversized locs and constant date files.
- Work the issue lines - Every finding carries a code and a file name: DUP_LOC for locations that appear twice, LASTMOD_INVALID for calendar or format failures, LOC_TOO_LONG for anything over 2048 characters, and more.
- Export the issues - Download the findings as CSV for a ticket, a spreadsheet, or a fix list for the team that generates the feed.
Lastmod, Duplicates and the Checks That Catch Broken Exports
Feed bugs follow patterns, and each check targets one:
- Strict lastmod parsing - W3C datetime form only, with real calendar validation. 2026-02-31 fails, banana fails, a datetime without a zone fails.
- Future dates - Anything beyond about two days ahead is flagged, because scheduled rewrites and clock skew both show up here.
- Constant lastmod files - When every URL in a file shares one date, the exporter is stamping a default instead of real change times. Crawl prioritization suffers quietly when this ships.
- Cross file duplicates - Locations are pooled across all children, so overlap between two child files surfaces immediately instead of causing duplicate crawl signals.
- Loc protocol lint - Missing locs, invalid URLs, bad schemes and anything over 2048 characters are errors, with insecure http reported as a warning.
- changefreq and priority - Enum values and the 0.0 to 1.0 range are validated so crawler hints stay valid.
Audit Sitemaps Without Fetching a Thing
Fetching a live sitemap index from this page would fail CORS on most hosts and still only see the index, not the children behind it. Local files sidestep both problems: drop the export your CMS produced and the audit merges everything in memory. Pair it with the Robots TXT Checker so crawlers can reach the files, the Canonical Tag Checker for indexation conflicts, or the Free SEO Audit Tool for a full crawl. Booking help? See our SEO audit services.
Frequently Asked Questions
What does this sitemap index validator check?
It reads a sitemap index and any child urlset files you provide, then reports document counts, child coverage, duplicate locations across files, invalid and future lastmod values, locations over 2048 characters, wrong schemes, constant lastmod dates per file, and bad changefreq or priority values.
Why should I drop the index and all child files together?
Browsers refuse to fetch sitemap files across domains, so a URL only audit hits CORS errors on most hosts. Dropping the index file plus its children together bypasses that completely and produces one merged report across every file.
What counts as a valid lastmod date?
W3C datetime form: a plain date like 2026-01-31, or an ISO 8601 datetime with a time and a zone such as 2026-01-31T12:00:00Z. The check is strict about real calendar days, so 2026-02-31 fails instead of silently rolling into March.
What does a constant lastmod warning mean?
Every URL in that file carries the same date. Real sites rarely change every page on one day, so a constant value usually means an exporter stamped a default. Future dates get their own warning.
How are duplicate locations found?
Locations from every child file are pooled and compared after trimming. A URL that appears in two files, or twice in one file, is listed once with the files it came from.
Can it read gzipped sitemaps?
Yes. Files that start with gzip magic bytes are decompressed with the browser native DecompressionStream, so .xml.gz archives work the same as plain XML.
Is my sitemap data uploaded?
No. Decompression, XML parsing, linting and the report all run in this tab. The files, the extracted URLs and the findings never leave your device.