diff --git a/nixarr/lib/arr-settings-options.nix b/nixarr/lib/arr-settings-options.nix
new file mode 100644
index 0000000..290d433
--- /dev/null
+++ b/nixarr/lib/arr-settings-options.nix
@@ -0,0 +1,93 @@
+# Utilities for defining *arr service settings, options, and configs.
+#
+# Copied from nixpkgs master as of 2025-11-11: https://raw.githubusercontent.com/NixOS/nixpkgs/cf540f8c9840457ed90a315dd635bceecb78495a/nixos/modules/services/misc/servarr/settings-options.nix
+{
+  lib,
+  pkgs,
+}: {
+  mkServarrSettingsOptions = name: port:
+    lib.mkOption {
+      type = lib.types.submodule {
+        freeformType = (pkgs.formats.ini {}).type;
+        options = {
+          update = {
+            mechanism = lib.mkOption {
+              type = with lib.types;
+                nullOr (enum [
+                  "external"
+                  "builtIn"
+                  "script"
+                ]);
+              description = "which update mechanism to use";
+              default = "external";
+            };
+            automatically = lib.mkOption {
+              type = lib.types.bool;
+              description = "Automatically download and install updates.";
+              default = false;
+            };
+          };
+          server = {
+            port = lib.mkOption {
+              type = lib.types.port;
+              description = "Port Number";
+              default = port;
+            };
+          };
+          log = {
+            analyticsEnabled = lib.mkOption {
+              type = lib.types.bool;
+              description = "Send Anonymous Usage Data";
+              default = false;
+            };
+          };
+        };
+      };
+      example = lib.options.literalExpression ''
+        {
+          update.mechanism = "internal";
+          server = {
+            urlbase = "localhost";
+            port = ${toString port};
+            bindaddress = "*";
+          };
+        }
+      '';
+      default = {};
+      description = ''
+        Attribute set of arbitrary config options.
+        Please consult the documentation at the [wiki](https://wiki.servarr.com/useful-tools#using-environment-variables-for-config).
+
+        WARNING: this configuration is stored in the world-readable Nix store!
+        For secrets use [](#opt-services.${name}.environmentFiles).
+      '';
+    };
+
+  mkServarrEnvironmentFiles = name:
+    lib.mkOption {
+      type = lib.types.listOf lib.types.path;
+      default = [];
+      description = ''
+        Environment file to pass secret configuration values.
+        Each line must follow the `${lib.toUpper name}__SECTION__KEY=value` pattern.
+        Please consult the documentation at the [wiki](https://wiki.servarr.com/useful-tools#using-environment-variables-for-config).
+      '';
+    };
+
+  mkServarrSettingsEnvVars = name: settings:
+    lib.pipe settings [
+      (lib.mapAttrsRecursive (
+        path: value:
+          lib.optionalAttrs (value != null) {
+            name = lib.toUpper "${name}__${lib.concatStringsSep "__" path}";
+            value = toString (
+              if lib.isBool value
+              then lib.boolToString value
+              else value
+            );
+          }
+      ))
+      (lib.collect (x: lib.isString x.name or false && lib.isString x.value or false))
+      lib.listToAttrs
+    ];
+}
diff --git a/nixarr/readarr-audiobook/default.nix b/nixarr/readarr-audiobook/default.nix
index 6f75ea6..92e9d68 100644
--- a/nixarr/readarr-audiobook/default.nix
+++ b/nixarr/readarr-audiobook/default.nix
@@ -6,9 +6,12 @@
 }:
 with lib; let
   cfg = config.nixarr.readarr-audiobook;
+  service-cfg = config.services.readarr-audiobook;
   globals = config.util-nixarr.globals;
   nixarr = config.nixarr;
   port = 9494;
+
+  arr-settings-options = import ../lib/arr-settings-options.nix {inherit lib pkgs;};
 in {
   options.nixarr.readarr-audiobook = {
     enable = mkOption {
@@ -69,6 +72,46 @@ in {
     };
   };
 
+  # A tweaked copy of services.readarr from nixpkgs
+  options.services.readarr-audiobook = {
+    enable = lib.mkEnableOption "Readarr-Audiobook, a Usenet/BitTorrent audiobook downloader";
+
+    dataDir = lib.mkOption {
+      type = lib.types.str;
+      description = "The directory where Readarr-Audiobook stores its data files.";
+    };
+
+    package = lib.mkPackageOption pkgs "readarr" {};
+
+    openFirewall = lib.mkOption {
+      type = lib.types.bool;
+      description = ''
+        Open ports in the firewall for Readarr-Audiobook.
+      '';
+    };
+
+    # Uses name in description to refer to
+    # `services.readarr-audiobook.environmentFiles`.
+    settings = arr-settings-options.mkServarrSettingsOptions "readarr-audiobook" port;
+
+    # Uses name in description to document `READARR__*` environment variables.
+    environmentFiles = arr-settings-options.mkServarrEnvironmentFiles "readarr";
+
+    user = lib.mkOption {
+      type = lib.types.str;
+      description = ''
+        User account under which Readarr-Audiobook runs.
+      '';
+    };
+
+    group = lib.mkOption {
+      type = lib.types.str;
+      description = ''
+        Group under which Readarr-Audiobook runs.
+      '';
+    };
+  };
+
   config = mkIf (nixarr.enable && cfg.enable) {
     assertions = [
       {
@@ -96,17 +139,30 @@ in {
       "d '${nixarr.mediaDir}/library/audiobooks'  0775 ${globals.libraryOwner.user} ${globals.libraryOwner.group} - -"
     ];
 
+    services.readarr-audiobook = {
+      enable = cfg.enable;
+      package = cfg.package;
+      settings.server.port = cfg.port;
+      openFirewall = cfg.openFirewall;
+      dataDir = cfg.stateDir;
+      user = globals.readarr-audiobook.user;
+      group = globals.readarr-audiobook.group;
+    };
+
     systemd.services.readarr-audiobook = {
       description = "Readarr-Audiobook";
       after = ["network.target"];
       wantedBy = ["multi-user.target"];
-      environment.READARR__SERVER__PORT = builtins.toString cfg.port;
+
+      # Uses name to define `READARR__*` environment variables.
+      environment = arr-settings-options.mkServarrSettingsEnvVars "readarr" service-cfg.settings;
 
       serviceConfig = {
         Type = "simple";
-        User = globals.readarr-audiobook.user;
-        Group = globals.readarr-audiobook.group;
-        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.stateDir}";
+        User = service-cfg.user;
+        Group = service-cfg.group;
+        EnvironmentFile = service-cfg.environmentFiles;
+        ExecStart = "${lib.getExe service-cfg.package} -nobrowser -data=${service-cfg.dataDir}";
         Restart = "on-failure";
       };
     };
diff --git a/nixarr/readarr/default.nix b/nixarr/readarr/default.nix
index a8e4606..c14b46a 100644
--- a/nixarr/readarr/default.nix
+++ b/nixarr/readarr/default.nix
@@ -94,19 +94,14 @@ in {
       "d '${nixarr.mediaDir}/library/books' 0775 ${globals.libraryOwner.user} ${globals.libraryOwner.group} - -"
     ];
 
-    systemd.services.readarr = {
-      description = "Readarr";
-      after = ["network.target"];
-      wantedBy = ["multi-user.target"];
-      environment.READARR__SERVER__PORT = builtins.toString cfg.port;
-
-      serviceConfig = {
-        Type = "simple";
-        User = globals.readarr.user;
-        Group = globals.readarr.group;
-        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.stateDir}";
-        Restart = "on-failure";
-      };
+    services.readarr = {
+      enable = cfg.enable;
+      package = cfg.package;
+      settings.server.port = cfg.port;
+      openFirewall = cfg.openFirewall;
+      dataDir = cfg.stateDir;
+      user = globals.readarr.user;
+      group = globals.readarr.group;
     };
 
     networking.firewall = mkIf cfg.openFirewall {