Slack uses PHP for most of its server-side application logic, which is an unusual choice these days. Why did we choose to build a new project in this language?

https://sekao.net/nightlight/

интересно

Nightlight is an editor you run inside your Clojure projects. Instead of being a separate application like traditional editors and IDEs, it's just a library that you add to your project. It spins up a web server and provides a completely browser-based interface to edit your code.