diff --git a/README.md b/README.md
index 296cf4c..5566d26 100644
--- a/README.md
+++ b/README.md
@@ -22,8 +22,11 @@ various configurations. Use it like a recipe book for when you write your own Wi
 Instructions:
 
 * Use Java 11
-* Run with `./gradlew programmatic:run`
-* Make a request to a stubbed endpoint with `curl --request GET --url http://localhost:8070/message`
+* Run:
+  * `./gradlew programmatic:run`
+* Make requests to the stubbed endpoints:
+  * `curl --request GET --url http://localhost:8070/message`
+  * `curl --request GET --url http://localhost:8070/random-integer`
 * Observe the Jetty server statistics by going to <http://localhost:8070/stats/> in your browser
   * Statistics include things like the number of responses with 200/300/400/500 status codes, the number of connections,
     and the amount of memory used by the underlying Jetty server.
@@ -44,7 +47,7 @@ Instructions:
 General clean-ups, changes and things I wish to implement for this project:
 
 * Make the sub-projects completely standalone and adhere to the convention I have in my other playground repos.
-* Add a stub with a custom handler that uses custom Java code to respond to the request.
+* DONE Add a stub with a custom handler that uses custom Java code to respond to the request.
 * Create a WireMock-in-Docker example
 * DONE create a sub-project that declares dependency constraint versions and which will be used as a `platform(...)`
   from the other projects. For details of this feature, see the [Gradle docs about "platform"](https://docs.gradle.org/current/userguide/platforms.html)
diff --git a/programmatic/src/main/java/dgroomes/wiremock/ProgrammaticMain.java b/programmatic/src/main/java/dgroomes/wiremock/ProgrammaticMain.java
index 4ecebdc..18a8fdf 100644
--- a/programmatic/src/main/java/dgroomes/wiremock/ProgrammaticMain.java
+++ b/programmatic/src/main/java/dgroomes/wiremock/ProgrammaticMain.java
@@ -16,8 +16,8 @@ public class ProgrammaticMain {
     private static final Logger log = LoggerFactory.getLogger(ProgrammaticMain.class);
     private static final int SLEEP_SECONDS = 30;
     private static final int PORT = 8070;
-//    private static final String ROOT_DIR = "wiremock/scenarios/happy-path";
-    private static final String ROOT_DIR = "wiremock/scenarios/occasional-failure";
+    private static final String ROOT_DIR = "wiremock/scenarios/happy-path";
+//    private static final String ROOT_DIR = "wiremock/scenarios/occasional-failure";
 
     public static void main(String[] args) throws InterruptedException {
         var start = Instant.now();
@@ -25,6 +25,7 @@ public static void main(String[] args) throws InterruptedException {
                 .port(PORT);
         WireMockUtil.configureStatistics(options);
         WireMockUtil.configureRootDir(options, ROOT_DIR);
+        WireMockUtil.configureExtensions(options);
         WireMockServer wireMockServer = new WireMockServer(options);
         log.debug("Starting the WireMock server");
         wireMockServer.start();
diff --git a/programmatic/src/main/java/dgroomes/wiremock/RandomIntegerTransformer.java b/programmatic/src/main/java/dgroomes/wiremock/RandomIntegerTransformer.java
new file mode 100644
index 0000000..ae550ff
--- /dev/null
+++ b/programmatic/src/main/java/dgroomes/wiremock/RandomIntegerTransformer.java
@@ -0,0 +1,45 @@
+package dgroomes.wiremock;
+
+import com.github.tomakehurst.wiremock.common.FileSource;
+import com.github.tomakehurst.wiremock.extension.Parameters;
+import com.github.tomakehurst.wiremock.extension.ResponseTransformer;
+import com.github.tomakehurst.wiremock.http.Request;
+import com.github.tomakehurst.wiremock.http.Response;
+
+import java.util.Random;
+
+/**
+ * Return a random integer. Optionally, when a "limit" argument is supplied, use that as the exclusive maximum value.
+ */
+public class RandomIntegerTransformer extends ResponseTransformer {
+
+    private Random random = new Random();
+
+    @Override
+    public String getName() {
+        return "random-integer-transformer";
+    }
+
+    @Override
+    public boolean applyGlobally() {
+        return false;
+    }
+
+    private String template = "{\n" +
+            "  \"random_integer\":" +
+            "  %d\n" +
+            "}";
+
+    @Override
+    public Response transform(Request request, Response response, FileSource files, Parameters parameters) {
+        if (parameters == null) {
+            parameters = new Parameters();
+        }
+
+        var limit = ((int) parameters.getOrDefault("limit", 100));
+        var randomInt = random.nextInt(limit);
+        return Response.response()
+                .body(String.format(template, randomInt))
+                .build();
+    }
+}
diff --git a/programmatic/src/main/java/dgroomes/wiremock/WireMockUtil.java b/programmatic/src/main/java/dgroomes/wiremock/WireMockUtil.java
index 8b85f21..3e155f4 100644
--- a/programmatic/src/main/java/dgroomes/wiremock/WireMockUtil.java
+++ b/programmatic/src/main/java/dgroomes/wiremock/WireMockUtil.java
@@ -133,4 +133,8 @@ public static void configureRootDir(WireMockConfiguration options, String rootDi
 
         options.withRootDirectory(rootDir);
     }
+
+    public static void configureExtensions(WireMockConfiguration options) {
+        options.extensions(new RandomIntegerTransformer());
+    }
 }
diff --git a/programmatic/wiremock/scenarios/happy-path/mappings/__files/random-integer.json b/programmatic/wiremock/scenarios/happy-path/mappings/__files/random-integer.json
new file mode 100644
index 0000000..639fb2f
--- /dev/null
+++ b/programmatic/wiremock/scenarios/happy-path/mappings/__files/random-integer.json
@@ -0,0 +1,11 @@
+{
+  "request": {
+    "urlPathPattern": "/random-integer(/?)",
+    "method": "GET"
+  },
+  "response": {
+    "transformers": [
+      "random-integer-transformer"
+    ]
+  }
+}