Health check endpoints in Express - Mini Project: Build & Apply

Health check endpoints

📖 Scenario: You are building a simple web server using Express.js. You want to add endpoints that let users check if the server is running and healthy.

🎯 Goal: Create two health check endpoints: /health that returns a simple status message, and /ready that returns a readiness message.

📋 What You'll Learn

Create an Express app instance called app

Add a GET endpoint /health that responds with JSON { status: 'ok' }

Add a GET endpoint /ready that responds with JSON { ready: true }

Make the app listen on port 3000

💡 Why This Matters

🌍 Real World

Health check endpoints help monitoring systems know if your server is running and ready to handle requests.

💼 Career

Many backend jobs require setting up health checks for services to ensure reliability and uptime.

1

Set up Express app

Create a variable called express by requiring the 'express' module. Then create an Express app instance called app by calling express().

Express

const express = require('express');
const app = express();
// Your code here

Need a hint?

Use require('express') to import Express and then call it to create app.

2

Add /health endpoint

Add a GET endpoint /health to the app that sends a JSON response with { status: 'ok' }.

Express

const express = require('express');
const app = express();

// Add GET /health endpoint here
// Your code here

Need a hint?

Use app.get('/health', (req, res) => { ... }) and inside send JSON with res.json({ status: 'ok' }).

3

Add /ready endpoint

Add a GET endpoint /ready to the app that sends a JSON response with { ready: true }.

Express

const express = require('express');
const app = express();

app.get('/health', (req, res) => {
  res.json({ status: 'ok' });
});

// Add GET /ready endpoint here
// Your code here

Need a hint?

Use app.get('/ready', (req, res) => { ... }) and inside send JSON with res.json({ ready: true }).

4

Start the server

Make the app listen on port 3000 using app.listen.

Express

const express = require('express');
const app = express();

app.get('/health', (req, res) => {
  res.json({ status: 'ok' });
});

app.get('/ready', (req, res) => {
  res.json({ ready: true });
});

// Start server on port 3000
// Your code here

Need a hint?

Use app.listen(3000) to start the server on port 3000.