diff --git a/modules/default.nix b/modules/default.nix
index 892719b..96bfba4 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -4,6 +4,7 @@
   amdgpu-pwm = ./services/hardware/amdgpu-pwm.nix;
   betanin = ./services/web-apps/betanin.nix;
   dunst = ./services/x11/dunst.nix;
+  porkbun-ddns = ./services/networking/porkbun-ddns.nix;
   radeon-profile-daemon = ./services/hardware/radeon-profile-daemon.nix;
 }
 
diff --git a/modules/services/networking/porkbun-ddns.nix b/modules/services/networking/porkbun-ddns.nix
new file mode 100644
index 0000000..ba512cc
--- /dev/null
+++ b/modules/services/networking/porkbun-ddns.nix
@@ -0,0 +1,74 @@
+{ config, lib, pkgs, ... }:
+let
+  inherit (lib) mkOption types;
+
+  cfg = config.services.porkbun-ddns;
+in
+{
+  options = {
+    services.porkbun-ddns = {
+      enable = lib.mkEnableOption "Porkbun dynamic DNS client";
+
+      package = mkOption {
+        # TODO: How do I use mkPackageOption when the package isn't in the
+        #  package set?
+        type = types.package;
+        default = (import ../../..).porkbun-ddns;
+        defaultText = "pkgs.porkbun-ddns";
+        description = lib.mdDoc "The porkbun-ddns package to use.";
+      };
+
+      interval = mkOption {
+        type = types.str;
+        default = "10m";
+        default = lib.mdDoc ''
+          Interval to update dynamic DNS records. The default is to update every
+          10 minutes. The format is described in {manpage}`systemd.time(7)`.
+        '';
+      };
+
+      domains = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        description = lib.mdDoc "Domains to update.";
+      };
+
+      apiKeyFile = mkOption {
+        type = types.nullOr types.path;
+        description = lib.mdDoc ''
+          File containing the API key to use when running the client.
+        '';
+      };
+
+      secretApiKeyFile = mkOption {
+        type = types.nullOr types.path;
+        description = lib.mdDoc ''
+          File containing the secret API key to use when running the
+          client.
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.services.porkbun-ddns = {
+      description = "Porkbun dynamic DNS client";
+      script = ''
+        ${cfg.package}/bin/porkbun-ddns \
+          -K ${cfg.apiKeyFile} \
+          -S ${cfg.secretApiKeyFile} \
+          ${lib.concatStringsSep " " cfg.domains}
+      '';
+    };
+
+    systemd.timers.porkbun-ddns = {
+      description = "Porkbun dynamic DNS client";
+      wants = [ "network-online.target" ];
+      wantedBy = [ "timers.target" ];
+      timerConfig = {
+        OnBootSec = cfg.interval;
+        OnUnitActiveSec = cfg.interval;
+      };
+    };
+  };
+}