gURL is described as 'free, Open Source (GPL) HTTP request generator tool' and is an app in the Development category. There are five alternatives to gURL for Mac, Windows and Linux. The best alternative is RESTClient, which is both free and Open Source. Other great apps like gURL are Graphical HTTP Client (Paid), Cocoa Rest Client (Free, Open Source), RESTtest (Paid) and Windows RestClient (Free, Open Source).
RESTtest is a simple yet intuitive way to test RESTful web services and standard HTTP calls. RESTtest allows you to enter a HTTP request body and any necessary headers. After the request is submitted, response information can be both viewed and saved to disk.