Making PHP interoperable with .NET is a worthy goal. A lot of PHP code is still in use, ... Old code gets to run on new systems, and new code gets to build on decades of PHP experience.

3] GNU Emacs. Next up, we have a cross-platform, open-source IDE for you to write and compile PHP codes on. GNU Emacs was first designed for a GNU-based OS, but now it supports Windows 10.

PhpDesigner (29€ for non-commercial use, 69€ for commercial use) is a full-fledged PHP, CSS, HTML, and JavaScript editor, with code completion and syntax highlighting for all four languages.