It is a really powerful, highly capable text editor for macOS and it's free! If you miss Notepad++ when using macOS, this is an excellent alternative.

I am a senior developer and I have been using Textmate for quite a long time. As Notepad++ is not available on macOS, this is the best alternative that anyone can think of. There is a number of options that allows you to customize the editor for any of your needs. I found the multiple Carets option really useful as it will allow you to make changes at multiple places at once. Also, there is File Search, Macros, Bundles, and more.

simple to use, it used to be great--now it's unsupported