nix-bun

A Nix flake that provides pre-built Bun binaries from official GitHub releases.

This flake downloads upstream release archives directly from oven-sh/bun.

Getting Started

# Run the latest version
nix run github:ryoppippi/nix-bun

# Run a specific version
nix run 'github:ryoppippi/nix-bun#"1.3.12"'

# Run explicit package attributes
nix run github:ryoppippi/nix-bun#bun

# Run the latest canary build
nix run github:ryoppippi/nix-bun#canary

Features

• ✅ Automatic updates via GitHub Actions
• ✅ Canary builds from Bun's rolling canary tag
• ✅ Multi-platform support: Linux (x86_64, aarch64) and macOS (x86_64, aarch64)
• ✅ Direct downloads from official Bun GitHub releases
• ✅ SHA256 verification using release asset digests
• ✅ Flake and non-flake support

Why Use This Flake?

nixpkgs already provides Bun, but this flake tracks the official pre-built release binaries directly from upstream.

Use this if you want:

• the exact binaries published by the Bun project
• faster packaging updates driven by GitHub Releases
• simple installation without rebuilding Bun from source

Usage

Quick Start

nix run github:ryoppippi/nix-bun

nix shell github:ryoppippi/nix-bun
bun --version

With Flakes

Add the input to your flake:

{
  inputs = {
    nix-bun.url = "github:ryoppippi/nix-bun";
  };
}

Then use nix-bun.packages.${system}.default directly, or add the overlay and reference pkgs.bun.

The flake provides both direct package outputs and overlay attributes:

• nix-bun.packages.${system}.bun
• pkgs.bun
• pkgs.bun-bin

Add to devShell

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nix-bun.url = "github:ryoppippi/nix-bun";
  };

  outputs = { nixpkgs, nix-bun, ... }:
    let
      systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
      forAllSystems = nixpkgs.lib.genAttrs systems;
    in
    {
      devShells = forAllSystems (system:
        let
          pkgs = nixpkgs.legacyPackages.${system};
        in
        {
          default = pkgs.mkShell {
            packages = [
              nix-bun.packages.${system}.default
            ];
          };
        }
      );
    };
}

Using the overlay

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nix-bun.url = "github:ryoppippi/nix-bun";
  };

  outputs = { nixpkgs, nix-bun, ... }:
    let
      systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
      forAllSystems = nixpkgs.lib.genAttrs systems;
    in
    {
      devShells = forAllSystems (system:
        let
          pkgs = import nixpkgs {
            inherit system;
            overlays = [ nix-bun.overlays.default ];
          };
        in
        {
          default = pkgs.mkShell {
            packages = [
              pkgs.bun
            ];
          };
        }
      );
    };
}

Add to devenv

devenv inputs add nix-bun github:ryoppippi/nix-bun

inputs:
  nix-bun:
    url: github:ryoppippi/nix-bun

{ pkgs, inputs, ... }:
{
  packages = [
    inputs.nix-bun.packages.${pkgs.system}.default
  ];
}

Without Flakes

let
  nix-bun = import (builtins.fetchTarball {
    url = "https://github.com/ryoppippi/nix-bun/archive/main.tar.gz";
  });
  pkgs = import <nixpkgs> {
    overlays = [ nix-bun.overlays.default ];
  };
in
  pkgs.bun

Version Pinning

You can install a specific version of Bun by using versioned package attributes:

nix-bun.packages.${system}."1.3.12"
nix-bun.packages.${system}.default

nix run 'github:ryoppippi/nix-bun#"1.3.12"'

All tracked versions are available in the versions/ directory.

Canary

The canary attribute tracks Bun's rolling canary release, built from main:

nix run github:ryoppippi/nix-bun#canary
nix shell github:ryoppippi/nix-bun#canary

nix-bun.packages.${system}.canary

Two caveats apply because canary is a rolling tag rather than an immutable release:

• Upstream replaces the assets on every build, so the pinned hashes in versions/canary.json go stale within hours. A build against outdated hashes fails with a hash mismatch — refresh the flake input (nix flake update nix-bun) to pick up the latest hourly update.
• Canary binaries report the unreleased base version (for example 1.4.0), so the package version carries the snapshot date instead: 1.4.0-unstable-2026-07-29. Use bun --revision to identify the exact commit.

canary is never selected as the default package; default and bun always point at the latest stable release.

How It Works

1. update.ts queries the official GitHub Releases API.
2. It reads release asset digests and converts them to SRI hashes.
3. GitHub Actions updates versions/*.json.
4. The flake installs the upstream release archive and exposes bun.

For canary, the version reported by the binaries cannot be derived from the tag, so it is read from package.json on Bun's main branch.

For x86_64 Linux and macOS, this flake uses Bun's -baseline assets for broader CPU compatibility.

Supported Platforms

• x86_64-linux
• aarch64-linux
• x86_64-darwin
• aarch64-darwin

Development

Development tooling is separated into dev/flake.nix to keep the consumer flake minimal.

Setup development environment

Option 1: Using direnv

direnv allow

Option 2: Manual

nix develop ./dev

Update sources manually

nix develop ./dev
./update.ts

Test the build

nix build
./result/bin/bun --version

Run checks manually

nix fmt ./dev
nix flake check ./dev