vic/gleam-nix

Build Gleam with Nix.

Source code at GitHub https://github.com/vic/gleam-nix/wiki/Historic-Builds

{
  "defaultBranch": "main",
  "description": "Build Gleam with Nix.",
  "fullName": "vic/gleam-nix",
  "homepage": "https://github.com/vic/gleam-nix/wiki/Historic-Builds",
  "language": "Nix",
  "name": "gleam-nix",
  "pushedAt": "2025-11-25T05:18:42Z",
  "stargazersCount": 30,
  "updatedAt": "2025-11-25T05:18:45Z",
  "url": "https://github.com/vic/gleam-nix"
}

Gleam on Nix

This repo provides packages and [development shells][devshell] for working with [Gleam] projects using Nix.

Usage

# running `gleam --version`
$ nix run github:vic/gleam-nix -- --version
gleam 1.9.0

# you can also override to use any gleam revision (commit,branch,release) and any rust version (prefer stable releases)
$ nix run github:vic/gleam-nix --override-input gleam github:gleam-lang/gleam/v1.9.1 --override-input rust-manifest file+https://static.rust-lang.org/dist/channel-rust-1.85.0.toml -- --version
gleam 1.9.1

For previous versions see Historic Builds

Hack with Gleam

If you are creating a new awesome project with Gleam, this flake can provide you with a development environment containing gleam and two of its run-times: erlang and nodejs.

$ nix run github:vic/gleam-nix -- new my-new-project
$ cd my-new-project
$ nix develop github:vic/gleam-nix -c $SHELL -l

If you are using [direnv], create an .envrc file with the following content:

use flake github:vic/gleam-nix

Hack on Gleam

If you are willing to contribute to Gleam development, this flake can provide you an entire development environment ready for you to focus only on making Gleam awesome.

$ git clone https://github.com/gleam-lang/gleam
$ cd gleam
$ nix develop github:vic/gleam-nix#hack-on-gleam --override-input gleam "path:$PWD" -c $SHELL -l

If you are using [direnv], create an .envrc file with the following content:

use flake github:vic/gleam-nix#hack-on-gleam --override-input gleam "path:$PWD"

Hack on this repo

$ nix develop .#hack-on-gleam-nix -c $SHELL -l

If you are using [direnv] this repo already contains an .envrc you can load.

Contributing

Yes, please :).

See [hack-on-gleam-nix]!(devshells/hack-on-gleam-nix.md)

Try not to change gleam pinned release unless it no longer builds with the current Rust toolchain. In that case, update the rust-manifest input and the gleam pinned release. And please update Historic Builds with the range of known versions able to build.

FAQ

How is this different from the gleam package provided by nixpkgs.

This flake existed before we had an official gleam package on nixpkgs. And most people would indeed only use that package.

However, for gleam hackers, this flake would be better suited since it provides a development shell with dependencies based on Gleam’s source.

Also people trying to use a more recent or experimental version of Gleam will benefit from this flake.
I’m getting a option 'allow-import-from-derivation' is disabled error.

Old versions of this repo bundled a Cargo.nix file containing all of Gleam’s dependencies in order for nix to know how to fetch them and how to build the Gleam cargo workspace.

However, one inconvenience of this was that the Cargo.nix file was tied to a particular Gleam revision, and since Gleam is improving quite rapidly, it was not uncommon to find the Cargo.nix file on this repo being outdated with respect to Gleam’s source code.

People had to regularly re-create the Cargo.nix file with cargo2nix.

Now, instead of using cargo2nix, we use crate2nix which allows us to generate the Cargo.nix file as part of the build. Thus not requiring we to bundle it on this repo, and prevent it from getting outdated. One advantage is that using --override-input gleam <some-gleam-url> will automatically generate Cargo.nix for that particular gleam revision.

This repo will only need to be updated when we have to bump the rust toolchain as expected by Gleam.

On the other side, by not bundling a Cargo.nix, building with crate2nix requires the allow-import-from-derivation nix option to be enabled.

This flake enables this option as part of flake.nix and will be activated if you are listed as trusted-user in your nix.conf or provide --accept-flake-config explicitly.

[devshell] !: https://numtide.github.io/devshell [direnv] !: https://direnv.net [gleam] !: https://gleam.run