Brackets is a modern editor that is really great for web design as it updates you page in a live view without having to Alt-Tab out of your editor.
As for any editor it is possible to write any languages in it and even enhance the experience with plug-ins. All the plug-ins can be downloaded in the Extension Manager built-in.
This plug-in is a must have for those who write Python, Ruby or some other scripting language. After installing it you can run the current script by tapping Ctrl(Cmd)-Alt-B on your keyboard.
If you want to add support for more languages you can do so by going into Edit then Edit Builder.
HTML Special Chars
This plug-in is also a must have for those dealing with special chars in HTML, it can replace them automatically when typed or can replace manually a selected string’s special chars by tapping Ctrl-Shift-N.
This plug-in isn’t a must have, but I like having my indent guides showing.
As a tab lover I indent my code with tabs. I know that for some people this is frown upon but whenever I write code for myself I use and will always use tabs.
This plug-in makes sure that all the indentation is made with tabs.
Inline Regex Editor
Put you cursor on a JS regex and tap Ctrl-E. This will enable you to do inline tests of your regex.
If you use GitHub a lot you must have already written a README.md file or some documentation in Markdown. Some sites are great for providing online editors sur as StackEdit.
Markdown Preview does all the previewing in Brackets.
Preferences setup UI
One of the biggest downsides of Brackets is that there is no settings UI. This plug-in fixes that.
Make that JSON string pretty printed.
This plug-in hints words in current documents. It adds autocomplete for PHP, Python, Perl and for some other languages.