What a sitemap does
An XML sitemap is a machine-readable list of the pages on your site that you want search engines to know about. It does not guarantee indexing and it is not a ranking factor, but it helps crawlers discover pages efficiently — particularly those that are poorly linked internally, newly published, or on a large site where crawling everything takes time.
If your site is small and every page is reachable within a few clicks from the homepage, a sitemap adds little. Its value grows with size, with how frequently you publish, and with how deep your structure runs.
What to include
Include only canonical URLs that you want indexed and that return a 200 status. This sounds obvious but is where most sitemaps go wrong. Common mistakes are including redirected URLs, pages that return 404, pages blocked in robots.txt, non-canonical duplicates, and paginated series pages.
A sitemap containing errors reduces trust in the whole file. Google Search Console reports these problems, and it is worth checking after submission rather than assuming the file is clean.
Use absolute URLs including the protocol, and be consistent about the www prefix and trailing slashes. Mixed conventions create duplicate signals.
The optional tags
The lastmod date is the one Google actually uses, and only when it is accurate. Setting every page's lastmod to today whenever you regenerate the file makes it worthless, and Google will start ignoring it. Set it to the date the page content genuinely last changed, or omit it.
Changefreq and priority are, in practice, ignored by Google entirely. Google has stated this plainly. They remain in the specification and other crawlers may use them, so including them does no harm, but do not spend time tuning them expecting a result.
Size limits
A single sitemap may contain up to 50,000 URLs and must not exceed 50MB uncompressed. Larger sites split across multiple files referenced from a sitemap index. Many sites also split by content type — one for pages, one for posts, one for products — which makes Search Console reporting considerably easier to read, since you can see which section has problems.
After you generate it
Upload the file to your site root, reference it in robots.txt with a Sitemap line, and submit it in Google Search Console. Submission prompts a fetch rather than guaranteeing indexing.
Generated in your browser
The file is built locally from the URLs you paste and nothing is transmitted.
Frequently Asked Questions
Does a sitemap improve rankings?
No. It aids discovery, which helps pages get found and indexed, but it is not a ranking factor in itself.
Do priority and changefreq matter?
Google ignores both. Only lastmod is used, and only when it accurately reflects genuine content changes.
How many URLs can one sitemap hold?
Up to 50,000 URLs and 50MB uncompressed. Larger sites split into multiple files referenced from a sitemap index.
What should I not include?
Redirected URLs, pages returning errors, non-canonical duplicates, and anything blocked in robots.txt. Errors reduce trust in the whole file.
Where do I put the file?
At your site root, referenced from robots.txt with a Sitemap line, then submitted through Google Search Console.