Imp 😈

Nix flakes require explicit imports. Add a module, update the imports list. Reorganize your directory structure, fix every relative path. Imp removes this busywork: point it at a directory and it imports everything inside, mapping filesystem paths to attribute names.

{ inputs, ... }:
{
  imports = [ (inputs.imp ./modules) ];
}

Add a file to modules/, it gets imported. Remove it, gone. No filepath bookkeeping.

Beyond imports

Directory-based imports are the foundation. Imp builds five more things on top:

Registries give modules names instead of paths. Instead of ../../../modules/nixos/base.nix, write registry.modules.nixos.base. Rename a directory and the migration tool scans for broken references, matches them to new paths by leaf name, and generates ast-grep commands to rewrite them.

Config trees map directory structure to NixOS option paths. The file programs/git.nix sets programs.git. Your directory layout becomes a visual index of what's configured.

Input collection scatters flake inputs next to the code that uses them. A formatter module declares its treefmt-nix dependency inline with __inputs; imp collects these and regenerates flake.nix.

Export sinks reverse the import direction. Features declare where their configuration should land (__exports."nixos.role.desktop"), and consumers import the merged result. Multiple features targeting the same sink merge according to their strategy. This decouples features from the hosts that use them.

Host declarations generate nixosConfigurations from __host attributes in the registry. Declare system, stateVersion, which sinks to import, and optional Home Manager integration. Imp assembles the configuration, no separate output file required.

Installation

{
  imp.treeWith lib (f: f { inherit pkgs; }) ./outputs
  # { packages.hello = <derivation>; apps.run = <derivation>; }
}

Export sinks

Features export configuration fragments to named sinks:

# registry/features/audio.nix
{
  __exports."desktop.nixos" = {
    value = { services.pipewire.enable = true; };
  };
}

The flake-parts module collects these and exposes them as flake.exports. Consumers import the merged sink:

{ exports, ... }:
{
  imports = [ exports.desktop.nixos.__module ];
}

Multiple features targeting the same sink merge according to their strategy (deep merge by default).

Host declarations

Define hosts in the registry with __host:

# registry/hosts/workstation/default.nix
{
  __host = {
    system = "x86_64-linux";
    stateVersion = "24.11";
    sinks = [ "desktop.nixos" ];
    hmSinks = [ "desktop.hm" ];
    user = "alice";
  };
  config = ./config;
}

Enable host generation in your flake config:

imp = {
  registry.src = ./registry;
  hosts.enable = true;
};

Imp scans for __host declarations and generates flake.nixosConfigurations.workstation. The sinks field imports export sinks; user wires up Home Manager integration. No separate nixosConfiguration file needed.

Optional features

Documentation generation and dependency visualization are opt-in modules with their own inputs.

Documentation with imp.docgen.

Run nix run .#visualize to analyze your registry and create a force graph visualization in the browser.

Documentation

Full docs

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