XML sitemap

A sitemap is an XML file, usually at /sitemap.xml, holding a url entry for each page with its address (loc) and, ideally, its last modified date (lastmod). The format, published at sitemaps.org, is shared by Google, Bing and most other engines. One file can hold up to 50,000 URLs or 50 MB uncompressed; bigger sites split into several files listed in a sitemap index, and extensions cover images, video and news.

Submit it in Search Console and Bing Webmaster Tools, or point to it with a Sitemap line in robots.txt. It helps pages get discovered but does not force them into the index. Google ignores the priority and changefreq fields and trusts lastmod only when it is consistently accurate. Most frameworks and CMSs generate one automatically.