Many SEO guides suggest creating XML Sitemaps. They either say or imply that sitemaps are needed to get Google to index your site and get good rankings. XML sitemaps do have some uses for SEO, but:
- XML sitemaps won't influence Google rankings.
- Google rarely chooses to index a URL that it only finds via an XML sitemap.
Sitemaps aren't required for good SEO. It is much more important to make sure that Googlebot can crawl your website. Every page should have links from several other pages.
The main way that Google ranks pages is based on external links. For search engine rankings, it is much more important to ask other sites to link to your pages than it is to build XML sitemaps.
So what are XML sitemaps good for?
XML sitemaps can get Googlebot to fully crawl the pages listed in them. This can be useful if you want Google to come take a look at a set of pages because they changed significantly. You can create a temporary XML sitemap with just those URLs and submit it to Google to crawl. Just keep in mind that Google doesn't base its decision on whether or not to index pages based on whether or not they are found in your sitemap.
Google prefers URLs in XML sitemaps when it encounters duplicate content. If you have two URLs on your site that show the same thing, Google will prefer to index the one in your XML sitemap. Alternatively you can use canonical tags or redirects as more powerful mechanisms to tell Google which URLs to prefer.
Google Search Console provides extra stats about URLs that are in your sitemap. When you submit an XML sitemap to search console, Google will tell you how many of its URLs are indexed. This can be useful for keeping a close eye on an important set of URLs from your site.
For further reading
The Sitemap Paradox - Webmasters Stack Exchange
This article was written as part of a series about SEO myths.