Like NPM for everything, but using Nix.
Devbox is a command-line tool that lets you easily create isolated shells for development.
You start by defining the list of packages required for your project, and Devbox creates an isolated, reproducible environment with those packages installed.
Update: This is game changer!
devbox global add can install almost everything the platform-specific package manger is needed for – up to now. Even on macOS Brew or MacPorts become less important.