# XML sitemaps

> A sitemap helps Google discover URLs, but does not guarantee crawling or indexing; well-linked sites may not need one. Each file is limited to 50 MB uncompressed or 50,000 URLs. Google ignores priority and changefreq, and uses lastmod only when it is consistently and verifiably accurate.

- URL: https://geo.casa/crawling-indexing/xml-sitemaps/
- Reference · Officially documented
- Reviewed: 2026-10-25

## Do you need one?

> **Officially documented:**
> If your site's pages are properly linked, Google can usually discover most of the site. A sitemap can improve crawling of larger or more complex sites. It "doesn't guarantee that all the items in your sitemap will be crawled and indexed."
>
> Sources: [Google Search Central: What is a sitemap](https://developers.google.com/search/docs/crawling-indexing/sitemaps/overview)

## Size limits

> **Officially documented:**
> "All formats limit a single sitemap to 50MB (uncompressed) or 50,000 URLs." Larger sites split into several sitemaps and can submit a single sitemap index file.
>
> Sources: [Google Search Central: Build and submit a sitemap](https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap)

> **Officially documented:**
> Baidu's sitemap protocol allows 50,000 URLs per file but requires each file to be under 10MB (10,485,760 bytes), also before gzip compression. It accepts XML and plain-text sitemaps and sitemap index files, in UTF-8 or GBK.
>
> Sources: [Baidu: 百度Sitemap协议](https://help.baidu.com/question?prod_id=99&class=0&id=3032)

> **Officially documented:**
> 360 Search uses the same 10MB and 50,000-URL limit per file, accepts UTF-8 or GBK, and caps a sitemap index file at 500MB.
>
> Sources: [360 Search: Sitemap介绍](https://www.so.com/help/help_3_3.html)

> **Officially documented:**
> Toutiao Search requires UTF-8 and caps each data file at 10MB and 10,000 items; a sitemap index may not exceed 5MB or 50,000 entries.
>
> Sources: [Toutiao Search: sitemap提交帮助](https://www.toutiao.com/i6766898464660914695/)

A file that suits Google's 50MB limit can be too large for the Chinese engines. Files under 10MB and 10,000 URLs fit all of them.

## Tags Google uses and ignores

> **Officially documented:**
> Google ignores `<priority>` and `<changefreq>` values. It uses `<lastmod>` "if it's consistently and verifiably (for example by comparing to the last modification of the page) accurate", and the value should reflect the last significant update.
>
> Sources: [Google Search Central: Build and submit a sitemap](https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap)

| Tag | Google |
|---|---|
| `<loc>` | Required: the canonical URL |
| `<lastmod>` | Used only when consistently accurate |
| `<priority>` | Ignored |
| `<changefreq>` | Ignored |

## What to include

- Only canonical, indexable URLs — no redirects, `noindex` pages or duplicates ([Canonical URL signals](https://geo.casa/crawling-indexing/canonical-signals/)).
- One `<lastmod>` per URL that changes when the page meaningfully changes, not on every rebuild.

## How this wiki does it

The sitemap lists only published, indexable entries in both languages — no drafts, fallback pages or thin hubs. Each `<lastmod>` is the entry's review date, the same date shown on the page and used as `dateModified` in its JSON-LD; there is no `<priority>` or `<changefreq>`.

## Related

- [XML sitemaps vs IndexNow](https://geo.casa/tools-protocols/sitemaps-vs-indexnow/) — pull (sitemaps) versus push (IndexNow).

## Sources

- [Google Search Central: What is a sitemap](https://developers.google.com/search/docs/crawling-indexing/sitemaps/overview)
- [Google Search Central: Build and submit a sitemap](https://developers.google.com/search/docs/crawling-indexing/sitemaps/build-sitemap)
- [sitemaps.org: Sitemaps XML format](https://www.sitemaps.org/protocol.html)
- [Baidu: 百度Sitemap协议](https://help.baidu.com/question?prod_id=99&class=0&id=3032)
- [360 Search: Sitemap介绍](https://www.so.com/help/help_3_3.html)
- [Toutiao Search: sitemap提交帮助](https://www.toutiao.com/i6766898464660914695/)