diff --git a/.gitignore b/.gitignore
index b6b402ed9..02fe5a078 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 .DS_Store
 bin
+sources
 assignments-solution
 node_modules
 npm-debug.log
@@ -8,3 +9,5 @@ yarn-error.log
 *.bkp
 
 week3/prep-exercise/server-demo/
+assignments/hackyourtemperature/sources/keys.js
+
diff --git a/assignments/config-files/jest.config.js b/assignments/config-files/jest.config.js
index 19ba9649e..463c210da 100644
--- a/assignments/config-files/jest.config.js
+++ b/assignments/config-files/jest.config.js
@@ -1,3 +1,4 @@
+console.log("Jest config loaded");
 export default {
   // Tells jest that any file that has 2 .'s in it and ends with either js or jsx should be run through the babel-jest transformer
   transform: {
diff --git a/assignments/hackyourtemperature/__tests__/app.test.js b/assignments/hackyourtemperature/__tests__/app.test.js
new file mode 100644
index 000000000..e1c294ffe
--- /dev/null
+++ b/assignments/hackyourtemperature/__tests__/app.test.js
@@ -0,0 +1,65 @@
+import app from "../app.js";
+import supertest from "supertest";
+import fetch from "node-fetch";
+
+jest.mock("node-fetch");
+const request = supertest(app);
+
+describe("POST /", () => {
+  it("Quick test", () => {
+    expect(1).toBe(1);
+  });
+});
+
+describe("Test GET /", () => {
+  test("Send hello to backend", async () => {
+    const res = await request.get("/");
+
+    expect(res.statusCode).toBe(200);
+    expect(res.text).toBe("hello from backend to frontend!");
+  });
+});
+
+describe("Test POST /weather", () => {
+  test("Return city name is required.", async () => {
+    const city = " ";
+
+    const res = await request.post("/weather").send({ cityName: city });
+
+    expect(res.statusCode).toBe(400);
+    expect(res.body).toEqual({ msg: "City name is required." });
+  });
+});
+
+//test the happy path: when the user sends a valid city name, the API returns weather data.
+describe("Test POST /weather", () => {
+  test("Return temperature data", async () => {
+    const city = "amsterdam";
+    fetch.mockResolvedValue({
+      ok: true,
+      json: async () => ({
+        name: "Amsterdam",
+        main: { temp: 286.78 },
+      }),
+    });
+    const res = await request.post("/weather").send({ cityName: city });
+
+    expect(res.statusCode).toBe(200);
+    expect(res.body.main.temp).toBe(286.78);
+  });
+});
+
+describe("Test POST /weather", () => {
+  test("Return city not found", async () => {
+    const city = "amsterddam";
+
+    fetch.mockResolvedValue({
+      ok: false,
+      json: async () => ({}),
+    });
+    const res = await request.post("/weather").send({ cityName: city });
+
+    expect(res.statusCode).toBe(400);
+    expect(res.body).toEqual({ weatherText: "City is not found!" });
+  });
+});
diff --git a/assignments/hackyourtemperature/app.js b/assignments/hackyourtemperature/app.js
new file mode 100644
index 000000000..312e70e45
--- /dev/null
+++ b/assignments/hackyourtemperature/app.js
@@ -0,0 +1,36 @@
+import express from "express";
+import fetch from "node-fetch";
+import { keys } from "./sources/keys.js";
+
+const app = express();
+app.use(express.json());
+app.use(express.urlencoded({ extended: false }));
+
+app.get("/", (req, res) => {
+  res.status(200).send(`hello from backend to frontend!`);
+});
+
+app.post("/weather", async (req, res) => {
+  const { cityName } = req.body;
+  if (!cityName || cityName.trim() === "") {
+    return res.status(400).json({ msg: "City name is required." });
+  }
+
+  const url = `https://api.openweathermap.org/data/2.5/weather?q=${encodeURIComponent(
+    cityName.trim()
+  )}&appid=${keys.API_KEY}`;
+
+  try {
+    const response = await fetch(url);
+    if (!response.ok) {
+      return res.status(400).json({ weatherText: "City is not found!" });
+    }
+    const data = await response.json();
+
+    return res.json({ main: data.main });
+  } catch (error) {
+    res.send(error);
+  }
+});
+
+export default app;
diff --git a/assignments/hackyourtemperature/babel.config.cjs b/assignments/hackyourtemperature/babel.config.cjs
new file mode 100644
index 000000000..fbb629af6
--- /dev/null
+++ b/assignments/hackyourtemperature/babel.config.cjs
@@ -0,0 +1,13 @@
+module.exports = {
+  presets: [
+    [
+      // This is a configuration, here we are telling babel what configuration to use
+      "@babel/preset-env",
+      {
+        targets: {
+          node: "current",
+        },
+      },
+    ],
+  ],
+};
diff --git a/assignments/hackyourtemperature/jest.config.js b/assignments/hackyourtemperature/jest.config.js
new file mode 100644
index 000000000..19ba9649e
--- /dev/null
+++ b/assignments/hackyourtemperature/jest.config.js
@@ -0,0 +1,8 @@
+export default {
+  // Tells jest that any file that has 2 .'s in it and ends with either js or jsx should be run through the babel-jest transformer
+  transform: {
+    "^.+\\.jsx?$": "babel-jest",
+  },
+  // By default our `node_modules` folder is ignored by jest, this tells jest to transform those as well
+  transformIgnorePatterns: [],
+};
diff --git a/assignments/hackyourtemperature/package.json b/assignments/hackyourtemperature/package.json
new file mode 100644
index 000000000..5ad612975
--- /dev/null
+++ b/assignments/hackyourtemperature/package.json
@@ -0,0 +1,28 @@
+{
+  "name": "hackyourtemperature",
+  "version": "1.0.0",
+  "main": "server.js",
+  "type": "module",
+  "scripts": {
+    "test": "jest",
+    "start": "node server.js",
+    "dev": "nodemon server.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "express": "^5.1.0",
+    "express-handlebars": "^8.0.1",
+    "node-fetch": "^3.3.2"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.28.5",
+    "@babel/preset-env": "^7.28.5",
+    "babel-jest": "^30.2.0",
+    "jest": "^30.2.0",
+    "nodemon": "^3.1.10",
+    "supertest": "^7.1.4"
+  }
+}
diff --git a/assignments/hackyourtemperature/server.js b/assignments/hackyourtemperature/server.js
new file mode 100644
index 000000000..7297c6dd8
--- /dev/null
+++ b/assignments/hackyourtemperature/server.js
@@ -0,0 +1,7 @@
+import app from "./app.js";
+
+const port = 3000;
+
+app.listen(port, () => {
+  console.log(`server is running on port ${port}`);
+});