API versioning strategies in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is API versioning and why is it important?

API versioning is a way to manage changes in an API over time. It helps keep old clients working while allowing new features or fixes in newer versions. This avoids breaking existing apps when the API changes.

beginner

Name three common API versioning strategies used in Express apps.

1. URI versioning (e.g., /v1/users)<br>2. Query parameter versioning (e.g., /users?version=1)<br>3. Header versioning (using custom headers like 'Accept-Version')

beginner

How does URI versioning work in Express?

URI versioning adds the version number directly in the URL path. For example, '/v1/users' and '/v2/users' are two versions. Express routes are set up to handle each version separately.

intermediate

What is a benefit of using header versioning over URI versioning?

Header versioning keeps URLs clean and consistent. Clients specify the version in HTTP headers, so the URL stays the same. This can be better for caching and hides version details from the URL.

beginner

Show a simple Express route example using URI versioning for version 1 and version 2.

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

app.get('/v1/users', (req, res) => {
  res.send('Users from API version 1');
});

app.get('/v2/users', (req, res) => {
  res.send('Users from API version 2 with new data');
});

app.listen(3000);

Which of these is NOT a common API versioning strategy?

A Header versioning

B Query parameter versioning

C Database versioning

D URI versioning

Database versioning is unrelated to API versioning strategies. The others are common ways to version APIs.

In URI versioning, where is the version number placed?

A In the URL path

B In the request body

C In the query string

D In the HTTP header

URI versioning places the version number directly in the URL path, like '/v1/resource'.

What is a key advantage of header versioning?

A Simplifies URL structure

B Makes URLs longer

C Requires no headers

D Breaks caching

Header versioning keeps URLs clean and simple by moving version info to headers.

Which Express method is used to define a route for a specific API version?

A app.listen()

B app.get()

C app.version()

D app.routeVersion()

app.get() defines a GET route; versioning is handled by the URL or headers, not a special method.

Why is API versioning important when updating an API?

A To avoid using HTTP headers

B To break old clients intentionally

C To make URLs longer

D To allow new features without breaking existing clients

Versioning lets you add features or fix bugs without breaking apps that use older API versions.

Explain the differences between URI versioning, query parameter versioning, and header versioning in APIs.

Think about where the version info is placed and how clients specify it.

Describe how you would implement API versioning in an Express app using URI versioning.

Focus on route setup and handling different versions.