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Nix O'matic

Reproducible environments. Made easy.

Spin up any environment in seconds with a single nix develop command. Mix and match packages from any nixpkgs revision — no install, no setup, fully reproducible.

Get started →GitHub ActionAgent Skill
$ nix develop 'https://nixomatic.com/?packages=cowsay' \
  --extra-experimental-features 'nix-command flakes' \
  --accept-flake-config \
  --command -- cowsay 'Hello, world!'

 _______________
< Hello, world! >
 ---------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

One command. Any environment.

Nix O'matic generates Nix flakes on-the-fly so you can get the exact tools you need, instantly.

Any package, any version

Request any package from nixpkgs by name, pin an exact version with nodejs@20.11.1, or lock to a precise revision with python3:3b93cf5.

No Nix? Need a sandbox?

Run any environment through the official nixos/nix Docker image — no Nix install required, and nothing touches your host. Perfect for trying before you install, or for running untrusted code in an isolated container even when Nix is already on your machine.

Fully reproducible

Every environment is generated from real nixpkgs revisions, so the shell you get today is the shell you'll get a year from now.

Mix revisions freely

Combine packages that only coexist across different nixpkgs revisions in a single shell — no dependency conflicts, no manual overlays.

CI/CD ready

Drop the GitHub Action into any workflow for reproducible CI environments with exactly the packages and versions you pin.

Built for AI agents

The Agent Skill lets Claude Code and Codex auto-detect dependencies and run your project in a configured Nix environment.

Read the docs →