I'm working for a website to convert the website URL to an SEO friendly URL. I plan to use this: mysite.com/category-name/pageid-123-page-name I looked at some similarly categorized, highly ranked websites. They have the same structure, except for one thing. In one case, the URL format was thissite.com/category-name/pageid-123-page-name.html Another was thatsite.com/category-name/pageid-123-page-name.php Now I know the text in URLs help with SEO. Is it more helpful to have a file extension? If yes, which one is better? Or if my current plan is okay, will it be better with a / at the end?