1. Check the project and Node.js

Open the existing practice project and inspect its files. Find package.json and read its "scripts" and "dependencies" sections.

In a terminal opened in the project, check that Node.js and npm are available:

node --version
npm --version

node --version
npm --version

You should see version numbers. Node.js runs JavaScript outside the browser; npm installs packages and records the project’s dependencies.

If package.json is not present, use the project’s documented command for creating or initializing the project. Do not replace an existing package.json, because it may contain settings the project needs.

2. Install Express

Run:

npm install express

npm install express

Express is a library that makes the server’s request-and-response work easier to write. Without it, Node.js can still create a server, but you would need to handle more low-level details yourself.

After the command finishes, inspect package.json again. Confirm that:

• express appears under "dependencies"
• npm may also have created or updated a lockfile

That change is important: the project now records that it depends on Express. Another person or machine can use that record to install the same dependency later.

3. Write the server’s three responsibilities

Open the project’s server entry file, or create the entry file specified by the project instructions. The file needs to do three separate jobs:

1. Import Express.
2. Create an Express application.
3. Start listening on a port.

It also needs one route so the browser receives a useful response.

Use this as a skeleton, filling in the missing values yourself:

const express = require("express");

const app = express();

app.get("/", (request, response) => {
  response.send(/* a short message that identifies your server */);
});

const port = /* choose the port specified by the project, or use 3000 */;

app.listen(port, () => {
  console.log(`Server listening on port ${port}`);
});

const express = require("express");

const app = express();

app.get("/", (request, response) => {
  response.send(/* a short message that identifies your server */);
});

const port = /* choose the port specified by the project, or use 3000 */;

app.listen(port, () => {
  console.log(`Server listening on port ${port}`);
});

Do not skip the distinction between request and response:

• request describes what the browser asked for.
• response is what your server sends back.
• app.get("/", ...) means “when a browser makes a GET request for the root path /, run this function.”
• response.send(...) ends that request with text the browser can display.
• app.listen(...) makes the program wait for incoming connections.

The callback passed to app.get does not run when the file is merely loaded. It runs later, when a request actually arrives. That is why starting the program and visiting the browser are two different events.

Choose a message that makes the result unmistakable, such as a sentence containing the project’s purpose or your own name. A plain message is useful here because it proves the server response is coming from your code rather than from a browser error page.

4. Start the server

Use the project’s documented start command. If the project does not define one, run Node with the server entry file you opened:

node <your-server-entry-file>

node <your-server-entry-file>

Replace the placeholder with the actual filename; do not type the angle brackets.

Leave this terminal running. A server that is listening has not finished like a short script—it is deliberately staying alive so it can receive requests.

Look at the terminal output. You should see the listening message from your app.listen callback.

Now open a browser and visit:

http://localhost:<your-port>

http://localhost:<your-port>

For example, if you chose port 3000, the address is:

http://localhost:3000

http://localhost:3000

You should see the message passed to response.send.

This is the complete request path:

The address has two meaningful parts:

• localhost means “this same computer.”
• The port identifies which listening program should receive the request.

5. Verify that the route is doing the work

Change only the message inside response.send(...) while the server is still running. Save the file, then refresh the browser.

Observe what happens:

• If the new message appears, your route is responding.
• If the old message remains, your running Node process may not reload changed files automatically. Stop it with Ctrl+C, start it again, and refresh.
• If the browser cannot connect, inspect the terminal for an error and check that the browser’s port matches the port passed to app.listen.

Then visit a different path, such as:

http://localhost:<your-port>/test

http://localhost:<your-port>/test

You will probably see an Express “Cannot GET” response. That is useful evidence: your server is reachable, but you only defined a route for /. A server can be running correctly while still having no handler for a particular path.

Return to / and confirm your intended message appears there.