2.home-manager/docs/manual/usage/modular-services.md

Modular Services

Home Manager supports nixpkgs modular services under . This is the Home Manager analog to the NixOS system.services namespace: each entry is an abstract service sourced from <nixpkgs/lib/services/lib.nix> with the upstream portable systemd module loaded into it, so service modules shipped with packages (e.g. pkgs.<name>.passthru.services.default) drop in unchanged -- the same module evaluates on NixOS and on Home Manager.

A minimal example -- run a one-shot user service from a package's modular service definition:

{ pkgs, ... }: {
  home.services.tunnel = {
    imports = [ pkgs.ghostunnel.passthru.services.default ];
    ghostunnel = {
      listen = "127.0.0.1:8443";
      target = "127.0.0.1:8080";
      cert = "/run/secrets/cert.pem";
      key = "/run/secrets/key.pem";
      allowAll = true;
    };
  };
}

This produces ~/.config/systemd/user/tunnel.service with the expected ExecStart, LoadCredential, and WantedBy=default.target.

Each service exposes the upstream NixOS-style schema: process.argv, systemd.lib, systemd.mainExecStart, systemd.service, systemd.services, systemd.sockets. Lifted units are translated from NixOS-style attrs (wantedBy, serviceConfig, unitConfig, environment, ...) into the section-based INI shape ({ Unit; Service; Install; }) that Home Manager's consumes. Only common keys are mapped explicitly; uncommon options remain reachable via unitConfig, serviceConfig, or socketConfig.

Sub-services (nested services.<sub> inside another service) and their units are dashed under the parent service name. The empty unit key "" denotes the service's primary unit (lifted to a unit named after the service itself); process.argv becomes the default ExecStart for that unit, which defaults to WantedBy=default.target.

Configuration data

Each service can declare configuration files via configData.<name>. These are materialized at $XDG_CONFIG_HOME/system-services/<service>/<name> (mirroring how NixOS lifts configData to environment.etc), with the absolute path injected back into configData.<name>.path so the service can refer to its files at a stable location:

{ config, ... }:
{
  home.services.demo = {
    process.argv = [ "/bin/myapp" "--config" config.home.services.demo.configData."app.toml".path ];
    configData."app.toml".text = ''
      port = 1234
    '';
  };
}

Scope notes

Home Manager mirrors the surface of nixpkgs' portable systemd module: services and sockets only. Other unit kinds Home Manager supports natively under (timers, paths, mounts, ...) are intentionally not modeled on home.services until upstream grows them, to keep both surfaces aligned.