Nix Flake Registry

Welcome to the Nix Flake Registry repository! This repository contains the default flake-registry.json file utilized by the Nix CLI. The flake registry serves as a convenient method for the Nix CLI to associate short names with flake URIs, such as linking nixpkgs to github:NixOS/nixpkgs/nixpkgs-unstable.

Usage

Mapped names from this registry are employed in two distinct contexts:

CLI

The registry allows for more concise invocations of nix run and other Nix commands.

For instance, when executing nix run nixpkgs#hello, the nixpkgs portion is resolved to the corresponding GitHub repository via the registry mapping.

Flake Inputs

When a flake output function refers to an input that has not been explicitly specified, the input is resolved using the registry.

Consider the following minimal flake.nix file:

{
  outputs = { self, nixpkgs }: { };
}

Here, self refers to the flake itself, while nixpkgs is resolved automatically through the registry.

NOTE: Although this feature offers convenience, we recommend explicitly listing all inputs, as the flake registry content may change over time.

Registry File Format

The file format is briefly documented here: https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-registry.html#registry-format.

Inclusion Policy

Inclusion criteria are evaluated based on the following considerations:

1. The namespace has a limited size.
2. Common names should be avoided to prevent confusion if a user mistypes an input in their flake.nix and it resolves to another input via the registry.
3. The shortcut must offer clear utility to the NixOS ecosystem; it is not intended to showcase random projects.
4. Project popularity is taken into account.

When submitting a PR, please acknowledge and refer to these policy points for argumentation.

If your goal is to get your project listed somewhere, consider submitting it to https://github.com/nix-community/awesome-nix/ instead.

NOTE: Some existing entries may not adhere to this policy due to historical reasons.

Publication Pipeline

By default, the Nix CLI is configured to fetch the registry at https://channels.nixos.org/flake-registry.json. This URL is proxied to this repository using Fastly: https://github.com/NixOS/nixos-org-configurations/blob/72adc59c5ba946c3d4844a920e9beefae12bbd49/terraform/channels.tf#L106-L116.