Structure of a Sitemap
A sitemap is an XML file that lists all the URLs of a website’s pages within a domain. It helps web crawlers, like those used by DuckDuckGo, Google, Yahoo, etc., find and index these pages.
Website structure and its sitemap
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>http://www.yourdomain.com/</loc>
<lastmod>2025-09-02</lastmod>
</url>
</urlset>In the sitemap structure, each URL must be placed inside a <url> tag. The page’s URL is defined in the <loc> tag, and the <lastmod> tag indicates the last time the page was updated.
Generating a Sitemap in Astro
To manually generate a sitemap in Astro, you need to create a file named sitemap.xml.ts or sitemap.xml.js and export a GET function like this:
export async function GET() {
const siteUrl = import.meta.env.SITE;
const result = `
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>${siteUrl}/</loc>
</url>
</urlset>
`.trim();
return new Response(result, {
headers: {
"Content-Type": "application/xml",
},
});
}It’s also worth noting that Astro offers the @astrojs/sitemap integration, which automatically generates the sitemap. Manual sitemap generation is only necessary when dealing with SSR (server-side rendered) pages, requiring a custom sitemap.
Don’t forget to add the following link to the <head> section of all your pages to indicate the path to your sitemap.xml:
<link rel="sitemap" href="/sitemap.xml" />Now, let’s look at a more practical example. We’ll build a sitemap that includes the published articles of a blog.
import { getPosts } from "@/lib/posts";
export async function GET() {
const siteUrl = import.meta.env.SITE;
const posts = await getPosts();
const result = `
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
<loc>${siteUrl}/</loc>
</url>
${posts
.map((post) => {
const lastMod = post.updatedAt ?? post.createdAt;
return `<url>
<loc>${siteUrl}/blog/${post.slug}/</loc>
<lastmod>${lastMod}</lastmod>
</url>`;
})
.join("\n")}
</urlset>
`.trim();
return new Response(result, {
headers: {
"Content-Type": "application/xml",
},
});
}The code above will generate something like this:
Example of a sitemap
