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Fonts and locales

Overview

Desktop readability depends on two declarative layers: font packages registered with Fontconfig, and glibc locales wired into /etc/locale.conf and the locale archive. Font packages belong in fonts.packages, not only environment.systemPackages, so Fontconfig can index them and build a system cache. Locale defaults live under i18n.*. Keyboard layout and timezone are separate: virtual-console maps use console.keyMap (default "us") or mirror XKB when console.useXkbConfig = true; graphical sessions use services.xserver.xkb.* or compositor settings (see Wayland and compositors); clock and calendar timezone is time.timeZone. None of those are i18n.* options.

Details

Installing fonts. fonts.packages lists font store paths (for example pkgs.dejavu_fonts). The module feeds those directories into Fontconfig’s cache generation. Putting fonts only in environment.systemPackages may install files without registering them for Fontconfig-aware apps. fonts.enableDefaultPackages (default false; renamed from enableDefaultFonts) adds a basic Unicode-oriented set when you want coverage without curating a list: dejavu_fonts, freefont_ttf, gyre-fonts, liberation_ttf, unifont, noto-fonts-cjk-sans, noto-fonts-cjk-serif, and noto-fonts-color-emoji. Icon and patched fonts (including Nerd Font variants) are packaged in nixpkgs under names like pkgs.nerd-fonts.*; attribute names change over time — check your channel rather than copying a fixed list.

With fonts.fontconfig.enable on by default, NixOS builds /etc/fonts (cache, default families, rendering rules); most desktop setups leave it enabled. Tune rendering under fonts.fontconfig.*: hinting.enable, hinting.style (none, slight, medium, full), and subpixel.rgba (none, rgb, bgr, vrgb, vbgr) for LCD subpixel order. fonts.fontconfig.includeUserConf (default true) keeps Fontconfig reading ~/.config/fontconfig/ — useful alongside Home Manager dotfile patterns for per-user overrides without rebuilding the system for every tweak.

System locale. i18n.defaultLocale sets the glibc locale name (default "en_US.UTF-8") used for LANG and as the baseline for messages, collation, and formats. Per-category overrides go in i18n.extraLocaleSettings (for example LC_TIME, LC_MONETARY) without changing the default LANG. Character set for a category can be adjusted with i18n.localeCharsets when you need non-UTF-8 encodings.

The locale archive comes from i18n.defaultLocale, i18n.extraLocaleSettings, and i18n.extraLocales. List additional locales in i18n.extraLocales (format "nl_NL.UTF-8/UTF-8") or set "all" to install every glibc locale — each entry adds eval and build cost, so list only what you need. The older i18n.supportedLocales option is largely auto-computed and deprecated for manual edits; prefer i18n.extraLocales when adding locales beyond what the defaults imply.

Examples

Minimal desktop fonts plus mixed locale categories (in configuration.nix):

{ pkgs, ... }: {
  fonts.enableDefaultPackages = true;
  fonts.packages = with pkgs; [
    noto-fonts
    # Check your nixpkgs channel for current nerd-fonts attribute names:
    nerd-fonts.jetbrains-mono
  ];

  i18n.defaultLocale = "en_US.UTF-8";
  i18n.extraLocaleSettings = {
    LC_TIME = "de_DE.UTF-8";
    LC_MONETARY = "de_DE.UTF-8";
  };

  console.useXkbConfig = true;
  services.xserver.xkb.layout = "us";
  time.timeZone = "Europe/Berlin";
}

Add a non-default locale without installing everything:

{
  i18n.defaultLocale = "en_US.UTF-8";
  i18n.extraLocales = [ "ja_JP.UTF-8/UTF-8" ];
}

See also

References