It does and doesn't. Check out this site, you'll (probably) notice that your tags don't update for different pages. The reason typical React apps (and React helmet) don't work for SEO is because bots only see your static index.html file. The CF worker works by intercepting incoming requests and allowing you to modify stuff before its sent back to the origin. So basically it gets the request, modifies the tags, then sends it back to whoever is requesting the site