Next.js stands out in modern web frameworks due to its ability to handle both frontend and backend logic in the same project. One of the standout features is the support for building server-side APIs within the project itself. This reduces the overhead of setting up a separate backend infrastructure.
If you’re working on a React-based application and need to build a backend for handling requests, Next.js API routes offer a straightforward path. Whether you’re building a small app or a large-scale project, you can write server-side functions with ease.
This guide focuses on how to build an API in Next.js using its native API support. From setting up your project to creating advanced route handlers, you’ll get practical steps backed by working examples. If you’re getting started with Next.js API development, this post will help you move confidently toward production-ready code.
What Are API Routes in Next.js?
Next.js API routes are backend endpoints that run server-side code directly inside a Next.js project. Unlike traditional web development stacks that separate the frontend and backend, Next.js lets you handle both in one codebase.
Each API route acts like a serverless function. You place your route handler in the pages/api folder (or app/api when using the App Router). When a request hits a route, the corresponding file runs on the server, responds with data, and exits.
This setup simplifies API development with Next.js. You don’t need to configure Express or another backend framework. Instead, you write logic inside standard route files, which respond to HTTP requests with JSON or other data formats.
# When Should You Use Next.js API Routes?
Use Next.js API routes when you:
- Need backend logic but want to keep everything in one repository
- Want to build a small or medium-sized project quickly
- Require server-side processing for form submissions, authentication, or third-party integrations
- Don’t need a full backend framework like Express or Nest.js
If your app grows large or requires complex infrastructure, you may eventually split your frontend and backend. But to get started, Next.js backend API routes work well.
Also Read: What is Next JS? – Key Benefits and Why You Should Adopt It?
How to Build APIs with Next.js: Step-by-Step Breakdown
Building APIs directly inside your Next.js project gives you full control over server-side logic without adding a separate backend. Let’s walk through each step involved in building and scaling API endpoints using the Next.js App Router.
Step 1: Set Up Your Next.js App
Before writing your first API route, you need to create a new Next.js application that includes support for API features.
Run this command in your terminal:
npx create-next-app@latest --api
This will scaffold a Next.js app with both frontend and backend capabilities built in. It also prompts you to choose between App Router and Pages Router.
Recommendation: Choose the App Router. It’s the modern approach to routing and supports the latest features, including co-located API route handlers using files like route.ts.
After setup, your folder structure will include an app directory, inside which you’ll place your API route files.
Step 2: Understand the Use Cases for Next.js APIs
Not every project needs API routes, but when it does, Next.js makes it simple to build powerful backend logic inside the same codebase. Here are common use cases:
# Creating Public APIs
You can publish open API endpoints directly from your project. For example, if you’re building a blog, you might expose public JSON data from GET routes.
# Acting as a Proxy to External Services
Use the Next.js API to interact with third-party tools (like Stripe, OpenAI, or Mailchimp) while keeping API keys hidden. This is one of the best use cases for Next.js serverless API routes.
# Handling Webhooks
Next.js API routes support incoming POST requests. This allows your app to process events sent by external services (e.g., payment events, signup actions).
# Custom Authentication Flows
You can build custom login or signup logic using Next.js backend development. With route handlers, you can set cookies, check passwords, or connect to identity providers.
These examples show how using Next.js for backend APIs can simplify your architecture without extra frameworks.
Step 3: Create Your First API Route
Next.js API routes are defined as route handlers inside your app/api directory. Each subfolder corresponds to an endpoint path.
For example:
app
└── api
└── users
└── route.ts
This file will automatically respond to requests at /api/users.
Here’s a basic GET handler:
export async function GET() {
return new Response(JSON.stringify({ message: 'Hello from API' }), {
status: 200,
headers: { 'Content-Type': 'application/json' },
});
}
To support POST, PUT, or DELETE, you export each handler function separately:
export async function POST(request: Request) {
const body = await request.json();
return new Response(JSON.stringify({ received: body }), {
status: 201,
});
}
This setup makes it easy to build an API with Next.js without adding Express or external libraries.
Step 4: Work with the Web Request and Response Objects
Next.js API routes use the modern Request and Response objects instead of legacy frameworks like Express. This aligns with current web standards and improves compatibility with serverless platforms.
You can access important parts of the request:
request.body– Raw payload or JSON submitted by the clientrequest.nextUrl– Full URL info including pathname and queryrequest.headers– Read custom or authentication headersrequest.cookies– Useful for session management
When responding, always set the correct status and headers:
export async function GET() {
return new Response(JSON.stringify({ status: 'success' }), {
status: 200,
headers: { 'Content-Type': 'application/json' },
});
}
This approach aligns with best practices in Next.js API development, keeping everything modern and minimal.
Step 5: Create Dynamic API Routes
Dynamic API routes allow you to build endpoints that depend on variables like IDs, usernames, or slugs. This is essential when working with user data, database records, or nested resources.
File example:
app
└── api
└── users
└── [id]
└── route.ts
In this file, the dynamic segment [id] maps to the incoming URL parameter.
Here’s how to use it:
export async function GET(
request: Request,
{ params }: { params: { id: string } }
) {
const { id } = params;
return new Response(JSON.stringify({ userId: id }), {
status: 200,
headers: { 'Content-Type': 'application/json' },
});
}
This flexibility makes Next.js backend API routes powerful for building REST-style endpoints that are clean and easy to organize.
Step 6: Use Next.js API Routes to Proxy External Requests
Proxying lets your backend forward requests to another service while modifying them as needed. This helps with security (keeping API keys server-side), formatting, and reducing complexity on the frontend.
Example:
export async function GET() {
const res = await fetch('https://api.weatherapi.com/data', {
headers: { Authorization: `Bearer ${process.env.API_KEY}` },
});
const data = await res.json();
return new Response(JSON.stringify(data), {
status: 200,
headers: { 'Content-Type': 'application/json' },
});
}
This shows how to use Next.js for backend APIs that need to handle third-party integrations. By proxying data, you protect credentials and manage rate limits more effectively.
Also Read: Next.js – Navigating the Future of Web Development
Step 7: Organize Shared Logic and Middleware
As you build more endpoints, repeating logic across files becomes a problem. That’s where shared logic helps.
For example, you might have an auth.ts file that verifies a token:
export async function checkAuth(request: Request) {
const token = request.headers.get('authorization');
if (!token || token !== process.env.SECRET_KEY) {
return new Response(JSON.stringify({ error: 'Unauthorized' }), {
status: 401,
});
}
return null;
}
Then inside any route:
export async function GET(request: Request) {
const authError = await checkAuth(request);
if (authError) return authError;
return new Response(JSON.stringify({ data: 'Secure content' }), {
status: 200,
});
}
This approach aligns with Next.js API best practices, where logic remains clear, testable, and separate from route definitions.
Step 8: Deployment and “SPA Mode” Considerations
Next.js provides multiple ways to take your application live, depending on your use case. Whether you want to run a traditional server or publish a fully static site, the framework supports both.
8.1 Standard Node.js Deployment
Using next start allows full access to features like:
- Route Handlers (Next.js API routes)
- Server Components
- Middleware
- Dynamic request handling
No extra setup is required. Just run:
npm run build npm start
This works well for apps using Next.js backend API features.
8.2 SPA / Static Export
For static sites, you can export your app as a Single-Page Application:
// next.config.ts
const nextConfig = {
output: 'export',
};
export default nextConfig;
In this mode:
- API routes and server logic won’t run
- GET handlers without dynamic data can be exported as static files
- All server features are disabled (e.g., cookies, request headers)
Use this only if your site doesn’t rely on backend functionality.
8.3 Deploying APIs on Vercel
Vercel is the best choice for projects using Next.js serverless API routes. Key benefits:
- Auto-deployment of API handlers as serverless functions
- Built-in rate limiting with Vercel Firewall
- Support for scheduled tasks using Cron Jobs
This is ideal for projects needing dynamic features without manual infrastructure setup.
Also Read: Serverless Architecture with Next.js: Simplifying Process with Dedicated Developers
Step 9: Know When to Skip API Routes
Not all data access needs to go through API routes.
If you’re only using the data internally (e.g., during server-side rendering), it’s better to fetch it directly using Server Components instead of sending a separate HTTP request.
Why skip API routes in this case?
- Reduces network calls
- Improves performance
- Simplifies code
Use Next.js API routes when the data will be accessed by external clients, or when you need a clear backend interface for your frontend to communicate with.
Also Read: What Are Node.js Modules? A Complete Guide
Need Help Building APIs with Next.js? Shiv Technolabs Can Support Your Project
Building production-ready APIs in Next.js takes more than just route handlers. You need secure authentication, scalable architecture, reliable deployment, and clean code structure. If you want to move faster or need technical expertise, the Next.js development team at Shiv Technolabs can support you.
Our team works with businesses across industries to:
- Build robust backend APIs using the App Router
- Integrate third-party services like Stripe, Firebase, or custom CRMs
- Handle middleware, validation, and role-based access control
- Structure full-stack applications using modern Next.js best practices
- Set up performance-ready deployment on platforms like Vercel or custom Node.js environments
Whether you’re starting from scratch or improving an existing codebase, we help you focus on growth while we take care of the backend logic.
Also Read: How Much Does It Cost to Hire a Next.js Developer in 2025?
Final Thoughts
This two-part guide showed how to build API with Next.js by using route handlers, working with requests, creating dynamic routes, and managing shared logic. You’ve now seen how Next.js API routes fit into full-stack workflows—from simple endpoints to real-world features like proxying and authentication.
Whether you’re building public endpoints, handling user data, or connecting to third-party platforms, Next.js web development makes it possible to manage both frontend and backend in one project.
If you’re looking for expert support to move faster or scale your app, Shiv Technolabs offers dedicated Next.js development services tailored for API development, integrations, and full-stack solutions.
👉 Connect with Shiv Technolabs to get started.
