API versioning strategies in Express - Mini Project: Build & Apply

API Versioning Strategies with Express

📖 Scenario: You are building a simple web API for a bookstore. Over time, you want to support different versions of the API so clients can choose which version to use without breaking their apps.

🎯 Goal: Create an Express server that supports two API versions: v1 and v2. Each version should have a route /books that returns a different message indicating the version.

📋 What You'll Learn

Create an Express app with a basic route for version 1 at /api/v1/books

Add a configuration variable to hold the current API version

Create a route for version 2 at /api/v2/books that returns a different message

Set up the Express app to listen on port 3000

💡 Why This Matters

🌍 Real World

APIs often need to support multiple versions so that old clients keep working while new features are added.

💼 Career

Understanding API versioning is important for backend developers working with web services and maintaining backward compatibility.

1

Set up Express and create the version 1 route

Create an Express app by requiring express and calling express(). Then create a GET route at /api/v1/books that sends the text 'Books API Version 1' as the response.

Express

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

// Your code here

Need a hint?

Use require('express') to import Express and express() to create the app. Then use app.get to define the route.

2

Add a configuration variable for the current API version

Create a constant variable called currentVersion and set it to the string 'v2' to represent the current API version.

Express

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

app.get('/api/v1/books', (req, res) => {
  res.send('Books API Version 1');
});

// Your code here

Need a hint?

Use const currentVersion = 'v2' to store the current API version.

3

Create the version 2 route with a different response

Add a GET route at /api/v2/books that sends the text 'Books API Version 2' as the response.

Express

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

app.get('/api/v1/books', (req, res) => {
  res.send('Books API Version 1');
});

const currentVersion = 'v2';

// Your code here

Need a hint?

Use app.get with the path /api/v2/books and send the correct response text.

4

Start the Express server on port 3000

Add code to make the Express app listen on port 3000 and log the message 'Server running on port 3000' when it starts.

Express

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

app.get('/api/v1/books', (req, res) => {
  res.send('Books API Version 1');
});

const currentVersion = 'v2';

app.get('/api/v2/books', (req, res) => {
  res.send('Books API Version 2');
});

// Your code here

Need a hint?

Use app.listen(3000, () => { console.log('Server running on port 3000') }) to start the server.