Difference between path and url routes helper rails
about_path -> '/about' about_url -> 'http://localhost:3000/about'
Note that about_url is the full URL http://localhost:3000/about (with localhost:3000 being replaced with the domain name, such as example.com, for a fully deployed site).
To get just /about, you use about_path. In the Rails Tutorial, we’ll follow the common convention of using the path form except when doing redirects, where we’ll use the url form. This is because after redirects the HTTP standard technically requires a full URL, although in most browsers it will work either way.