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What are API Routes?

In this tutorial, we will delve into a critical feature of Next.js - API Routes. Understanding API Routes is vital as it forms the basis for building full-fledged applications with Next.js. So, let's get started!

What are API Routes in Next.js?​

In traditional web development, you generally have a separate backend and frontend. Your backend, often developed with languages like Node.js, Python, or Ruby, is responsible for handling all the API (Application Programming Interface) requests and responses. Your frontend, typically developed with HTML, CSS, and JavaScript, then consumes these APIs to display data to the user.

However, Next.js provides a feature called API Routes, which allows you to write backend logic directly within your Next.js application. It means you can create API endpoints inside your Next.js application without needing a separate backend service.

How to Create an API Route?​

Creating an API Route in Next.js is surprisingly simple. You just need to create a file inside the pages/api directory, and Next.js will automatically treat it as an API endpoint.

Let's take a look at an example:

// pages/api/hello.js

export default function handler(req, res) {
  res.status(200).json({ text: 'Hello' })
}

Here, we create a file named hello.js inside the pages/api directory. This file exports a function - handler, which becomes the API endpoint. The handler function receives two arguments: req (the request object) and res (the response object). In this example, we send a JSON response with the status code 200 (which means "OK") and a JSON object { text: 'Hello' }.

Now, if you navigate to http://localhost:3000/api/hello (assuming your Next.js application is running on http://localhost:3000), you will see the JSON response { text: 'Hello' }.

Request and Response Objects​

The req and res objects are instances of http.IncomingMessage and http.ServerResponse, respectively. These are the same objects you would receive in a Node.js server.

The req object includes information about the incoming request, such as headers, query string, and so on.

The res object is used to craft the server's response to the client. You can set the status code, headers, and body content using this object.

Summary​

API Routes in Next.js is an extremely powerful feature that allows you to write server-side code directly within your Next.js application. It simplifies the process of building full-stack applications by eliminating the need for a separate backend.

In the next tutorial, we will discuss more about API Routes, such as how to handle different HTTP methods, how to parse request bodies, and more. But for now, this should give you a good understanding of what API Routes are and how to create them.