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At this moment our website both uses the language in the url like "en" and localizes the url itself ("books" in english and "boeken" in dutch). Because of the history of making our website multilingual we have a system that takes the browser language for the localization if the url doesn't contain a language like "en". This means: www.test.com/books = browser language www.test.com/en/books = english language www.test.com/boeken = browser language www.test.com/nl/boeken = dutch language Now for the sitemap this makes it a little troublesome for me because which hreflang is used for which url? 1) The first thing I thought of was using x-default for all urls that get the language of the browser. <code><url><loc>http://www.test.com/books</loc></url></code> But as you can see we now got 2 times x-default. 2) Another solution I thought of was just use the localization of the url to determine the language like: <code><url><loc>http://www.test.com/books</loc></url></code> But now we got 2 of each language for the same page. 3) The last solution I thought of was removing links without a language in the url (except for the homepage, which will still have an x-default) like: <code><url><loc>http://www.test.comen/books</loc></url></code> But for this solution I need to put 301's at pages that are "deleted" and also need to change the system to 301 to the right page. Although the last point isn't really a problem I'm kind of worried that I will lose some of the "seo points" with a 301. (When we changed our domain in the past we had a bad experience with the 301 of our old domain) What do you think would be the best solution for SEO? Or do you have any other suggestions or solutions I haven't thought of.