Sitemap
XML file listing all URLs on your site — helps search engines (Google, Bing) discover content. Standard since 2005 (Google, Microsoft, Yahoo agreement).
Common location: /sitemap.xml, registered in robots.txt. Per URL: loc (URL), lastmod (last change), changefreq, priority. Sitemap index for sites with > 50k URLs or > 50MB. Images, video, news have special variants. Google Search Console + Bing Webmaster Tools let you submit sitemaps manually. Modern SSG tools (Next.js, Astro, Hugo) generate automatically. WordPress SEO plugins too.