I have an input field where the user can post a link to a facebook page. Right now I am using regex to validate the URL. URL_regex = /\A(http|https|ftp):\/\/([\w]*)\.([\w]*)\.(com|net|org|biz|info|mobi|us|cc|bz|tv|ws|name|co|me)(\.[a-z]{1,3})?/i I only want the following four versions to pass the validation: - `https://www.facebook.com/redbull` - `http://www.facebook.com/redbull` - `www.facebook.com/redbull` - `facebook.com/redbull` Then I want to only want to store the "redbull" part in the database. I tried [Rubular][1] but I can't figure out the logic of the regex. Thanks in advance **Found a solution, thx to caley:** URL_regex = /\A((http|https):\/\/)?(www\.)?facebook\.com\/([\S]+)/i [1]: http://www.rubular.com/