A list of pages on a website that should be indexed by search engines. A sitemap XML can be read by humans and computers since it is written in extensible markup language (XML). They include modification dates in addition to page URLs, so search engines can identify if a page has been crawled since it was last updated. Search engine optimization (SEO) techniques based on sitemap XML and robots.txt use distinct approaches to indexing. Robots.txt indicates “no,” while Sitemap XML says “yes.”