diff --git a/14-rock-paper-scissors/default.nix b/14-rock-paper-scissors/default.nix
new file mode 100644
index 0000000..ee9c4df
--- /dev/null
+++ b/14-rock-paper-scissors/default.nix
@@ -0,0 +1,87 @@
+{ pkgs, lib, sbt-derivation }:
+
+let
+  pname = "rock-paper-scissors";
+  package = sbt-derivation.lib.mkSbtDerivation {
+    inherit pkgs pname;
+    # ...and the rest of the arguments
+    version = "0.0.1";
+    src = pkgs.nix-gitignore.gitignoreSource [ ] ./.;
+    nativeBuildInputs = [ pkgs.nodePackages.tailwindcss ];
+    buildPhase = ''
+      tailwindcss -i ./src/input.css -o ./src/main/resources/public/output.css
+      sbt assembly
+    '';
+    # css path different from ordinary development,
+    # because .gitignore makes it unavailable during nix build
+    # anyway copied to correct place
+    installPhase = ''
+      mkdir -p $out/bin
+      cp target/scala-*/${pname}-assembly-*.jar $out/bin/${pname}.jar
+    '';
+
+    depsSha256 = "sha256-Y5RktcE3fxUJci4o7LTuNlBEybTdVRqsG551AkVeRPw=";
+  };
+
+  module = { config, pkgs, ... }:
+    let cfg = config.services.${pname};
+    in {
+      options.services.${pname} = {
+        enable = lib.mkEnableOption "My frontendmentor exercise ${pname}";
+
+        port = lib.mkOption {
+          type = lib.types.int;
+          default = 8080;
+          description = "Port to listen on.";
+        };
+
+        host = lib.mkOption {
+          type = lib.types.str;
+          default = "localhost";
+          description = "Host to bind to.";
+        };
+
+        useNginx = lib.mkOption {
+          type = lib.types.bool;
+          default = true;
+          description = "Whether to use Nginx to proxy requests.";
+        };
+      };
+      config = lib.mkIf cfg.enable {
+        users.groups."${pname}-group" = { };
+        users.users."${pname}-user" = {
+          isSystemUser = true;
+          group = "${pname}-group";
+        };
+
+        systemd.services.${pname} =
+          let serverHost = if cfg.useNginx then "localhost" else cfg.host;
+          in {
+            description = "Exercise app ${pname}";
+            wantedBy = [ "multi-user.target" ];
+            after = [ "network.target" ];
+            startLimitIntervalSec = 30;
+            startLimitBurst = 10;
+            serviceConfig = {
+              ExecStart =
+                "${pkgs.jdk}/bin/java -jar ${package}/bin/${pname}.jar -p ${
+                  toString cfg.port
+                } --host ${serverHost}";
+              WorkingDirectory = "${package}/bin";
+              Restart = "on-failure";
+              User = "${pname}-user";
+              Group = "${pname}-group";
+            };
+          };
+
+        services.nginx = lib.mkIf cfg.useNginx {
+          virtualHosts.${cfg.host} = {
+            locations."/".proxyPass = "http://127.0.0.1:${toString cfg.port}";
+          };
+        };
+      };
+    };
+in {
+  package = package;
+  module = module;
+}
diff --git a/flake.nix b/flake.nix
index da26672..3c1abc6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -23,6 +23,10 @@
           inherit pkgs sbt-derivation;
           lib = pkgs.lib;
         };
+        rock-paper-scissors = import ./14-rock-paper-scissors/default.nix {
+          inherit pkgs sbt-derivation;
+          lib = pkgs.lib;
+        };
       in {
         devShells.default = pkgs.mkShell {
           buildInputs = [
@@ -40,6 +44,8 @@
         nixosModules.order-summary = order-summary.module;
         packages.testimonials-grid = testimonials-grid.package;
         nixosModules.testimonials-grid = testimonials-grid.module;
+        packages.rock-paper-scissors = rock-paper-scissors.package;
+        nixosModules.rock-paper-scissors = rock-paper-scissors.module;
       });
   # see https://serokell.io/blog/practical-nix-flakes
 }