XML files are simple text documents which means they can be opened with any basic text editor. All operation systems (Windows, Mac, Linux, ..) come with native text editors, so there is no need to download external software to be able to write, view or edit those files.
However, specialized software editors can make editing XML files a lot easier, since they have additional features included such as coloring specific segments of code, auto-complete functions, etc.
You can edit XML files on Windows with Notepad, Mac OS X comes with TextEdit and Linux has many different tools for text file manipulation. The most basic are nano, Emacs and Pico.
We will present some best text editors for making your life easier when working with XML files.
Notepad++
Notepad++ is the popular, open-source software, written for all platforms. It has all the features you will ever need. You can get it here.
TextMate
TextMate is probably the best text editor for a Mac. It is not free, but it is definitely one of the most advanced tools used by the professionals. You can read more about it here.
UltraEdit
UltraEdit is a popular Windows text editor. The software is commercial, but it comes with some advanced features that might come handy for specific tasks.
Read more information here.