Reproducible builds and deployments.

Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. Share your development and build environments across different machines.

NixOS is a Linux distribution with a unique approach to package and configuration management. Built on top of the Nix package manager, it is completely declarative, makes upgrading systems reliable, and has many other advantages.

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Nix builds packages in isolation from each other. This ensures that they are reproducible and don't have undeclared dependencies, so if a package works on one machine, it will also work on another.


Nix makes it trivial to share development and build environments for your projects, regardless of what programming languages and tools you’re using.


Nix’s ensures that installing or upgrading one package cannot break other packages. It allows you to roll back to previous versions, and ensures that no package is in an inconsistent state during an upgrade.


Try new tools without fear

Don't clutter your system with tools that you use only now and then.

python --version
python: command not found
nix-shell -p python3
(nix-shell)python --version
Python 3.7.7

One tool, multiple languages

nix-shell -p python3 nodejs go rustc
(nix-shell)node --version
(nix-shell)go version
go version go1.14.1 linux/amd64
(nix-shell)rustc --version
rustc 1.42.0

Isolated development environments

After you get familiar with nix-shell -p you can take the next step further and learn some Nix. To setup a more persistent environment you can also write a simple shell.nix file:

{ pkgs ? import <nixpkgs> {}
pkgs.mkShell {
  name = "dev-shell";
  buildInputs = [

Then enter development environment with:

(nix-shell)virtualenv --version
(nix-shell)yarn --version

Commit the above shell.nix file and let you coworkers have easier time setting their development environment.

Minimal docker image

Declarative way to build minimal docker images. No build tools inside docker image, no complex multi stage build process, only what your application needs.

The following Nix expression (default.nix) defines a docker image with only Python 3 installed in it.

{ pkgs ? import <nixpkgs> {}
pkgs.dockerTools.buildLayeredImage {
  name = "only-hello";
  contents = [ pkgs.hello ];

To build and run the image you need to:

docker load -i ./result
Loaded image: only-hello:fgzj21lg3hjv8bxlaabcsfjkh4fg5ssk
docker run only-hello hello"
Hello World

Learn more how to build docker images.

Declarative cloud images

How hard would it be to build and configure a Amazon EC2 image?

With the following amazon.nix we defined nginx which is serving example /var/www folder, having a valid ssl certificate (via LetsEncrypt) and enabled recommended security settings.

{ pkgs, ...}:
  security.acme.acceptTerms = true; = "";
  services.nginx = {
    enable = true;
    recommendedGzipSettings = true;
    recommendedOptimisation = true;
    recommendedProxySettings = true;
    recommendedTlsSettings = true;
    virtualHosts."" = {
      enableACME = true;
      forceSSL = true;
      locations."/".root = "/var/www";

Now we just need to build it.

nix-build '<nixpkgs/nixos/release.nix>' \
    -A amazonImage.x86_64-linux \
    --arg configuration ./amazon.nix \
    -o ./result
ls ./result/