From NixOS Wiki

Nixpkgs is the largest repository of Nix packages and NixOS modules. The repository is hosted on GitHub and maintained by the community, with official backing from the NixOS Foundation.

To search among available packages, see Searching packages.

As highlighted in the announcement of the NixOS 21.05 release, "NixOS is already known as the most up to date distribution and is in the top three by total number of packages." This is thanks to the community's continued dedication to making Nixpkgs the preeminent Linux package repository.


There are a number of articles especially related to working with nixpkgs:


Main article: Channel branches

The packages and modules hosted on Nixpkgs are distributed through various channel branches intended for particular use-cases. In practice they are differentiated by the level of testing updates must pass on the official Hydra instance and the number of updates they receive.

For standalone Nix users, nixpkgs-unstable channel branch is the rolling release, where packages pass only basic build tests and are upgraded continuously.

For NixOS users, nixos-unstable channel branch is the rolling release, where packages pass build tests and integration tests on a VM, and are tested from the perspective of being an operative system (this means things like the X server, KDE, various servers, and lower level details like installing bootloaders and runnning the NixOS installation steps are also tested).

Both Nix and NixOS users can use stable channel branches - the latest being nixos-23.11 - to receive only conservative updates for fixing critical bugs and security vulnerabilities.


Due to the fact that Nixpkgs is only a Nix expression, it is possible to extend or replace the logic with your own sources. In fact, there are a number of extensions as well as complete replacements for Nixpkgs, see the Alternative Package Sets article.