diff --git a/nixarr/default.nix b/nixarr/default.nix
index 1e97de4..cc112ad 100644
--- a/nixarr/default.nix
+++ b/nixarr/default.nix
@@ -82,6 +82,10 @@ with lib; let
         chown -R readarr:root "${cfg.readarr.stateDir}"
         find "${cfg.readarr.stateDir}" \( -type d -exec chmod 0700 {} + -true \) -o \( -exec chmod 0600 {} + \)
       ''
+      + strings.optionalString cfg.readarr-audiobook.enable ''
+        chown -R readarr:root "${cfg.readarr-audiobook.stateDir}"
+        find "${cfg.readarr-audiobook.stateDir}" \( -type d -exec chmod 0700 {} + -true \) -o \( -exec chmod 0600 {} + \)
+      ''
       + strings.optionalString cfg.jellyseerr.enable ''
         chown -R jellyseerr:root "${cfg.jellyseerr.stateDir}"
         find "${cfg.jellyseerr.stateDir}" \( -type d -exec chmod 0700 {} + -true \) -o \( -exec chmod 0600 {} + \)
@@ -109,6 +113,7 @@ in {
     ./prowlarr
     ./radarr
     ./readarr
+    ./readarr-audiobook
     ./recyclarr
     ./sabnzbd
     ./sonarr
@@ -150,12 +155,13 @@ in {
         - [Prowlarr](#nixarr.prowlarr.enable)
         - [Radarr](#nixarr.radarr.enable)
         - [Readarr](#nixarr.readarr.enable)
+        - [Readarr Audiobook](#nixarr.readarr-audiobook.enable)
         - [Recyclarr](#nixarr.recyclarr.enable)
         - [SABnzbd](#nixarr.sabnzbd.enable)
         - [Sonarr](#nixarr.sonarr.enable)
         - [Transmission](#nixarr.transmission.enable)
 
-        Remember to read the options.
+        Remember to read the options!
       '';
     };
 
diff --git a/nixarr/prowlarr/default.nix b/nixarr/prowlarr/default.nix
index b1c0cbb..6a1ed81 100644
--- a/nixarr/prowlarr/default.nix
+++ b/nixarr/prowlarr/default.nix
@@ -5,26 +5,31 @@
   ...
 }:
 with lib; let
-  defaultPort = 9696;
-  nixarr = config.nixarr;
   cfg = config.nixarr.prowlarr;
+  nixarr = config.nixarr;
+  uid = 293;
+  port = 9696;
 in {
-  imports = [
-    ./prowlarr-module
-  ];
-
   options.nixarr.prowlarr = {
     enable = mkOption {
       type = types.bool;
       default = false;
       example = true;
       description = ''
-        Whether or not to enable the Prowlarr service.
+        Whether or not to enable the Prowlarr service. This has
+        a seperate service since running two instances is the standard
+        way of being able to query both ebooks and audiobooks.
       '';
     };
 
     package = mkPackageOption pkgs "prowlarr" {};
 
+    port = mkOption {
+      type = types.port;
+      default = port;
+      description = "Port for Prowlarr to use.";
+    };
+
     stateDir = mkOption {
       type = types.path;
       default = "${nixarr.stateDir}/prowlarr";
@@ -75,29 +80,52 @@ in {
       }
     ];
 
-    util-nixarr.services.prowlarr = {
-      enable = true;
-      package = cfg.package;
-      openFirewall = cfg.openFirewall;
-      dataDir = cfg.stateDir;
+    systemd.tmpfiles.rules = [
+      "d '${cfg.dataDir}' 0700 ${cfg.user} ${cfg.group} - -"
+    ];
+
+    systemd.services.prowlarr = {
+      description = "prowlarr";
+      after = ["network.target"];
+      wantedBy = ["multi-user.target"];
+      environment = {
+        PROWLARR__SERVER__PORT = cfg.port;
+      };
+
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.stateDir}";
+        Restart = "on-failure";
+      };
     };
 
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [cfg.port];
+    };
+
+    users.users.prowlarr = {
+      group = "prowlarr";
+      home = cfg.stateDir;
+      uid = uid;
+    };
+    users.groups.prowlarr = {};
+
     # Enable and specify VPN namespace to confine service in.
     systemd.services.prowlarr.vpnConfinement = mkIf cfg.vpn.enable {
       enable = true;
       vpnNamespace = "wg";
     };
 
-    # Port mappings
     vpnNamespaces.wg = mkIf cfg.vpn.enable {
       portMappings = [
         {
-          from = defaultPort;
-          to = defaultPort;
+          from = cfg.port;
+          to = cfg.port;
         }
       ];
     };
-
     services.nginx = mkIf cfg.vpn.enable {
       enable = true;
 
@@ -105,17 +133,17 @@ in {
       recommendedOptimisation = true;
       recommendedGzipSettings = true;
 
-      virtualHosts."127.0.0.1:${builtins.toString defaultPort}" = {
+      virtualHosts."127.0.0.1:${builtins.toString cfg.port}" = {
         listen = [
           {
             addr = "0.0.0.0";
-            port = defaultPort;
+            port = cfg.port;
           }
         ];
         locations."/" = {
           recommendedProxySettings = true;
           proxyWebsockets = true;
-          proxyPass = "http://192.168.15.1:${builtins.toString defaultPort}";
+          proxyPass = "http://192.168.15.1:${builtins.toString cfg.port}";
         };
       };
     };
diff --git a/nixarr/prowlarr/prowlarr-module/default.nix b/nixarr/prowlarr/prowlarr-module/default.nix
deleted file mode 100644
index d327a94..0000000
--- a/nixarr/prowlarr/prowlarr-module/default.nix
+++ /dev/null
@@ -1,77 +0,0 @@
-{
-  config,
-  pkgs,
-  lib,
-  ...
-}:
-with lib; let
-  cfg = config.util-nixarr.services.prowlarr;
-in {
-  options = {
-    util-nixarr.services.prowlarr = {
-      enable = mkEnableOption "Prowlarr";
-
-      package = mkPackageOption pkgs "prowlarr" {};
-
-      user = mkOption {
-        type = types.str;
-        default = "prowlarr";
-        description = "User account under which Prowlarr runs.";
-      };
-
-      group = mkOption {
-        type = types.str;
-        default = "prowlarr";
-        description = "Group under which Prowlarr runs.";
-      };
-
-      dataDir = mkOption {
-        type = types.str;
-        default = "/var/lib/prowlarr";
-        description = "The directory where Prowlarr stores its data files.";
-      };
-
-      openFirewall = mkOption {
-        type = types.bool;
-        default = false;
-        description = "Open ports in the firewall for the Prowlarr web interface.";
-      };
-    };
-  };
-
-  config = mkIf cfg.enable {
-    systemd.tmpfiles.rules = [
-      "d '${cfg.dataDir}' 0700 ${cfg.user} ${cfg.group} - -"
-    ];
-
-    systemd.services.prowlarr = {
-      description = "Prowlarr";
-      after = ["network.target"];
-      wantedBy = ["multi-user.target"];
-
-      serviceConfig = {
-        Type = "simple";
-        User = cfg.user;
-        Group = cfg.group;
-        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.dataDir}";
-        Restart = "on-failure";
-      };
-    };
-
-    networking.firewall = mkIf cfg.openFirewall {
-      allowedTCPPorts = [9696];
-    };
-
-    users.users = mkIf (cfg.user == "prowlarr") {
-      prowlarr = {
-        group = cfg.group;
-        home = cfg.dataDir;
-        uid = 293;
-      };
-    };
-
-    users.groups = mkIf (cfg.group == "prowlarr") {
-      prowlarr = {};
-    };
-  };
-}
diff --git a/nixarr/readarr-audiobook/default.nix b/nixarr/readarr-audiobook/default.nix
new file mode 100644
index 0000000..a3da61b
--- /dev/null
+++ b/nixarr/readarr-audiobook/default.nix
@@ -0,0 +1,151 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+with lib; let
+  cfg = config.nixarr.readarr-audiobook;
+  nixarr = config.nixarr;
+  uid = 269;
+  port = 9494;
+in {
+  options.nixarr.readarr-audiobook = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      example = true;
+      description = ''
+        Whether or not to enable the Readarr Audiobook service. This has
+        a seperate service since running two instances is the standard
+        way of being able to query both ebooks and audiobooks.
+      '';
+    };
+
+    package = mkPackageOption pkgs "readarr" {};
+
+    port = mkOption {
+      type = types.port;
+      default = port;
+      description = "Port for Readarr Audiobook to use.";
+    };
+
+    stateDir = mkOption {
+      type = types.path;
+      default = "${nixarr.stateDir}/readarr-audiobook";
+      defaultText = literalExpression ''"''${nixarr.stateDir}/readarr-audiobook"'';
+      example = "/nixarr/.state/readarr-audiobook";
+      description = ''
+        The location of the state directory for the Readarr Audiobook service.
+
+        > **Warning:** Setting this to any path, where the subpath is not
+        > owned by root, will fail! For example:
+        >
+        > ```nix
+        >   stateDir = /home/user/nixarr/.state/readarr-audiobook
+        > ```
+        >
+        > Is not supported, because `/home/user` is owned by `user`.
+      '';
+    };
+
+    openFirewall = mkOption {
+      type = types.bool;
+      defaultText = literalExpression ''!nixarr.readarr-audiobook.vpn.enable'';
+      default = !cfg.vpn.enable;
+      example = true;
+      description = "Open firewall for Readarr Audiobook";
+    };
+
+    vpn.enable = mkOption {
+      type = types.bool;
+      default = false;
+      example = true;
+      description = ''
+        **Required options:** [`nixarr.vpn.enable`](#nixarr.vpn.enable)
+
+        Route Readarr Audiobook traffic through the VPN.
+      '';
+    };
+  };
+
+  config = mkIf (nixarr.enable && cfg.enable) {
+    assertions = [
+      {
+        assertion = cfg.vpn.enable -> nixarr.vpn.enable;
+        message = ''
+          The nixarr.readarr-audiobook.vpn.enable option requires the
+          nixarr.vpn.enable option to be set, but it was not.
+        '';
+      }
+    ];
+
+    systemd.tmpfiles.rules = [
+      "d '${cfg.dataDir}' 0700 ${cfg.user} ${cfg.group} - -"
+    ];
+
+    systemd.services.readarr-audiobook = {
+      description = "Readarr-Audiobook";
+      after = ["network.target"];
+      wantedBy = ["multi-user.target"];
+      environment = {
+        READARR__SERVER__PORT = cfg.port;
+      };
+
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.stateDir}";
+        Restart = "on-failure";
+      };
+    };
+
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [cfg.port];
+    };
+
+    users.users.readarr-audiobook = {
+      group = "readarr-audiobook";
+      home = cfg.stateDir;
+      uid = uid;
+    };
+    users.groups.readarr-audiobook = {};
+
+    # Enable and specify VPN namespace to confine service in.
+    systemd.services.readarr-audiobook.vpnConfinement = mkIf cfg.vpn.enable {
+      enable = true;
+      vpnNamespace = "wg";
+    };
+
+    vpnNamespaces.wg = mkIf cfg.vpn.enable {
+      portMappings = [
+        {
+          from = cfg.port;
+          to = cfg.port;
+        }
+      ];
+    };
+    services.nginx = mkIf cfg.vpn.enable {
+      enable = true;
+
+      recommendedTlsSettings = true;
+      recommendedOptimisation = true;
+      recommendedGzipSettings = true;
+
+      virtualHosts."127.0.0.1:${builtins.toString cfg.port}" = {
+        listen = [
+          {
+            addr = "0.0.0.0";
+            port = cfg.port;
+          }
+        ];
+        locations."/" = {
+          recommendedProxySettings = true;
+          proxyWebsockets = true;
+          proxyPass = "http://192.168.15.1:${builtins.toString cfg.port}";
+        };
+      };
+    };
+  };
+}
diff --git a/nixarr/readarr/default.nix b/nixarr/readarr/default.nix
index 5241b90..f314481 100644
--- a/nixarr/readarr/default.nix
+++ b/nixarr/readarr/default.nix
@@ -7,7 +7,8 @@
 with lib; let
   cfg = config.nixarr.readarr;
   nixarr = config.nixarr;
-  defaultPort = 8787;
+  uid = 250;
+  port = 8787;
 in {
   options.nixarr.readarr = {
     enable = mkOption {
@@ -21,6 +22,12 @@ in {
 
     package = mkPackageOption pkgs "readarr" {};
 
+    port = mkOption {
+      type = types.port;
+      default = port;
+      description = "Port for Readarr to use.";
+    };
+
     stateDir = mkOption {
       type = types.path;
       default = "${nixarr.stateDir}/readarr";
@@ -71,31 +78,52 @@ in {
       }
     ];
 
-    services.readarr = {
-      enable = cfg.enable;
-      package = cfg.package;
-      user = "readarr";
-      group = "media";
-      openFirewall = cfg.openFirewall;
-      dataDir = cfg.stateDir;
+    systemd.tmpfiles.rules = [
+      "d '${cfg.dataDir}' 0700 ${cfg.user} ${cfg.group} - -"
+    ];
+
+    systemd.services.readarr = {
+      description = "Readarr";
+      after = ["network.target"];
+      wantedBy = ["multi-user.target"];
+      environment = {
+        READARR__SERVER__PORT = cfg.port;
+      };
+
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${lib.getExe cfg.package} -nobrowser -data=${cfg.stateDir}";
+        Restart = "on-failure";
+      };
     };
 
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [cfg.port];
+    };
+
+    users.users.readarr = {
+      group = "readarr";
+      home = cfg.stateDir;
+      uid = uid;
+    };
+    users.groups.readarr = {};
+
     # Enable and specify VPN namespace to confine service in.
     systemd.services.readarr.vpnConfinement = mkIf cfg.vpn.enable {
       enable = true;
       vpnNamespace = "wg";
     };
 
-    # Port mappings
     vpnNamespaces.wg = mkIf cfg.vpn.enable {
       portMappings = [
         {
-          from = defaultPort;
-          to = defaultPort;
+          from = cfg.port;
+          to = cfg.port;
         }
       ];
     };
-
     services.nginx = mkIf cfg.vpn.enable {
       enable = true;
 
@@ -103,17 +131,17 @@ in {
       recommendedOptimisation = true;
       recommendedGzipSettings = true;
 
-      virtualHosts."127.0.0.1:${builtins.toString defaultPort}" = {
+      virtualHosts."127.0.0.1:${builtins.toString cfg.port}" = {
         listen = [
           {
             addr = "0.0.0.0";
-            port = defaultPort;
+            port = cfg.port;
           }
         ];
         locations."/" = {
           recommendedProxySettings = true;
           proxyWebsockets = true;
-          proxyPass = "http://192.168.15.1:${builtins.toString defaultPort}";
+          proxyPass = "http://192.168.15.1:${builtins.toString cfg.port}";
         };
       };
     };
diff --git a/nixarr/readarr/readarr-module/default.nix b/nixarr/readarr/readarr-module/default.nix
new file mode 100644
index 0000000..3933ec0
--- /dev/null
+++ b/nixarr/readarr/readarr-module/default.nix
@@ -0,0 +1,93 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+let
+  cfg = config.services.readarr;
+  servarr = import ./settings-options.nix { inherit lib pkgs; };
+in
+{
+  options = {
+    services.readarr = {
+      enable = lib.mkEnableOption "Readarr, a Usenet/BitTorrent ebook downloader";
+
+      dataDir = lib.mkOption {
+        type = lib.types.str;
+        default = "/var/lib/readarr/";
+        description = "The directory where Readarr stores its data files.";
+      };
+
+      package = lib.mkPackageOption pkgs "readarr" { };
+
+      openFirewall = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = ''
+          Open ports in the firewall for Readarr
+        '';
+      };
+
+      settings = servarr.mkServarrSettingsOptions "readarr" 8787;
+
+      environmentFiles = servarr.mkServarrEnvironmentFiles "readarr";
+
+      user = lib.mkOption {
+        type = lib.types.str;
+        default = "readarr";
+        description = ''
+          User account under which Readarr runs.
+        '';
+      };
+
+      group = lib.mkOption {
+        type = lib.types.str;
+        default = "readarr";
+        description = ''
+          Group under which Readarr runs.
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.tmpfiles.settings."10-readarr".${cfg.dataDir}.d = {
+      inherit (cfg) user group;
+      mode = "0700";
+    };
+
+    systemd.services.readarr = {
+      description = "Readarr";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      environment = servarr.mkServarrSettingsEnvVars "READARR" cfg.settings;
+
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Group = cfg.group;
+        EnvironmentFile = cfg.environmentFiles;
+        ExecStart = "${cfg.package}/bin/Readarr -nobrowser -data='${cfg.dataDir}'";
+        Restart = "on-failure";
+      };
+    };
+
+    networking.firewall = lib.mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.settings.server.port ];
+    };
+
+    users.users = lib.mkIf (cfg.user == "readarr") {
+      readarr = {
+        description = "Readarr service";
+        home = cfg.dataDir;
+        group = cfg.group;
+        isSystemUser = true;
+      };
+    };
+
+    users.groups = lib.mkIf (cfg.group == "readarr") {
+      readarr = { };
+    };
+  };
+}