figsoda/unnix

---

figsoda/unnix.json

{
  "createdAt": "2026-02-04T05:56:09Z",
  "defaultBranch": "main",
  "description": "Reproducible Nix environments without installing Nix",
  "fullName": "figsoda/unnix",
  "homepage": "",
  "language": "Rust",
  "name": "unnix",
  "pushedAt": "2026-06-04T02:07:03Z",
  "stargazersCount": 106,
  "topics": [
    "cache",
    "ci",
    "devbox",
    "hydra",
    "nix",
    "nixos"
  ],
  "updatedAt": "2026-06-04T02:07:00Z",
  "url": "https://github.com/figsoda/unnix"
}

unnix

Reproducible Nix environments without installing Nix

Usage

[!Warning] Unnix is alpha software. I recommend against running it on long-running production servers in its current state.

Try with Nix flakes	Install from crates.io	Download prebuilt binaries
nix shell github:figsoda/unnix	cargo install unnix --locked	latest release

To use unnix, start by creating unnix.kdl, [unnix’s manifest file]!(docs/manifest.md)

unnix init -p jq ripgrep

Now you can enter the environment with

unnix env

This will generate unnix.lock.json and put you in a shell with jq and rg. Make sure to commit the lockfile to your VCS to keep your environment reproducible.

How it works

This is a very simplified view of what happens when you run nix develop.

flowchart TB

nix(nix) --> | download | expr --> | evaluate | drv
drv --> | outputs | path --> | query | cache

cache -->| hit | download(download to the Nix store)
cache -->| miss | build(build the derivation)
drv -.- build

cache(
  binary cache
  e.g. cache.nixos.org
)

drv(derivations)

expr(
  Nix expressions
  e.g. Nixpkgs
)

path(store paths)

Downloading and evaluating Nixpkgs can take a long time, especially in ephemeral environments like CI pipelines. Unnix avoids that by removing derivations from the picture altogether, and getting the store paths directly from services like [Hydra] or [Devbox].

flowchart TB
unnix --> | lockfile absent or outdated | update --> | Hydra / Devbox | paths
unnix --> | up-to-date lockfile | paths
paths --> | query | cache

cache --> | hit | download(download to the unnix store)
cache --> | miss | miss

cache(
  binary cache
  e.g. cache.nixos.org
)

miss(
  fail
)

paths(store paths)

unnix(unnix)

update(update lockfile)

Platform support

	aarch64-darwin	aarch64-linux	x86_64-darwin	x86_64-linux
CLI	partial[^1]	yes	partial[^1]	yes
[GitHub action]	yes	yes	no	yes
[prebuilt binaries]	yes	yes	no	yes
cached by the default cache	yes	yes	yes[^2]	yes

[^1] !: unnix env relies on [bubblewrap], which only works on Linux. An alternative darwin backend is work in progress.

[^2] !: x86_64-darwin will be deprecated in Nixpkgs 26.11.

Limitations

• No setup hooks

  Unnix does not have access to stdenv, and therefore cannot run the setup hooks or any user-specified shellHooks. Instead, it tries its best to emulate the behavior of setup hooks like pkg-config, so that dependencies can be picked up without executing any hooks.

• No evaluation

  Unnix does not evaluate Nix expressions. You cannot use .override or .overrideAttrs on packages, and are limited to the attributes the resolver exposes, e.g. [Hydra] jobs.

• No builds

  Unnix cannot build anything, and strictly relies on binary caches. This means no unfree packages if you are using the default set of caches.

Related projects

• nix-bundle

• runix

Documentation

See [docs/README.md]!(docs)

Changelog

See [CHANGELOG.md]!(CHANGELOG.md)

[Devbox] !: https://www.nixhub.io/ [GitHub action] !: https://github.com/figsoda/unnix-action [Hydra] !: https://github.com/nixos/hydra [bubblewrap] !: https://github.com/containers/bubblewrap [prebuilt binaries] !: https://github.com/figsoda/unnix/releases