GitHub’s Atom Editor is a popular Code Editor for Developers. It can be installed for free on Windows, Mac, and Linux and includes built-in support for PHP.
A widely used PHP Server plugin/package is recommended here for development with PHP.
PHP Server Package
When you install PHP on your computer you can then use the PHP Server extension with Atom to launch a site. It works perfectly with FastSitePHP, simply right-click on the [index.php] file and select [PHP Server here].
You will then see FastSitePHP launch (or the starter site) in your default browser.