Modern web applications increasingly rely on APIs to exchange data between the frontend, backend, and third-party services. Whether you are building dashboards, mobile apps, or integrating enterprise systems, APIs are at the core of scalable architectures. For an Odoo Consultant, understanding frameworks like Next.js is especially valuable, as it enables seamless integration between ERP systems and modern web interfaces. Next.js simplifies backend development by allowing developers to build API endpoints directly within the same project used for the frontend.

This blog provides a step-by-step guide to building your first API endpoint in Next.js, focusing on the App Router approach introduced in newer versions. By the end, you’ll understand how API routes work, how to handle different HTTP methods, and how to follow best practices for building secure and maintainable endpoints.

Understanding API Routes in Next.js

Next.js API routes allow you to create REST-style backend endpoints without setting up a separate server like Express or Fastify. These endpoints run on the server and can securely access databases, environment variables, and authentication logic.

You can use API routes for:

• Fetching and saving data

• Authenticating users

• Handling form submissions

• Integrating third-party services

• Receiving webhooks

With the App Router, API routes live inside the app/api directory, making them intuitive and well-organized.

Project Structure for API Routes

In Next.js (version 13+ with App Router), API routes follow a folder-based structure. Each folder represents an endpoint, and a route.js or route.ts file defines how that endpoint behaves.

Example structure:

In this example, visiting /api/hello will trigger the logic defined inside route.ts.

Step 1: Setting Up a Next.js Project

If you don’t already have a Next.js application, creating one is straightforward. Use the official CLI tool:

During setup, choose TypeScript if prompted, as it improves code quality and developer experience. Once the development server is running, your app will be accessible at http://localhost:3000.

Step 2: Creating Your First API Endpoint

To create your first API endpoint:

1. Inside the app directory, create a folder called api

2. Inside api, create another folder (for example, hello)

3. Add a file named route.ts

Now, define a simple GET handler:

When you open http://localhost:3000/api/hello in your browser, you’ll receive a JSON response. This confirms that your endpoint is working correctly.

Step 3: Supporting Multiple HTTP Methods

One of the strengths of Next.js API routes is built-in support for multiple HTTP methods. You can define separate functions for GET, POST, PUT, or DELETE within the same route.ts file.

Example:

This allows a single endpoint to handle different operations based on the request method, making your API design clean and RESTful.

Step 4: Working with Query Parameters

Query parameters are commonly used to filter or customize responses. Next.js makes them accessible through the standard URL API.

Example endpoint:

Visiting /api/greet?name=Sarah will return a personalized response. This approach is useful for search, filtering, and pagination.

Step 5: Connecting API Routes to a Database

API routes are often used to interact with databases. You can connect to any database supported by Node.js, such as PostgreSQL, MySQL, or MongoDB.

A popular choice is Prisma, which provides type-safe database access.

Example GET endpoint using Prisma:

This allows your API route to securely fetch data and return it as JSON, ready for use by your frontend or external systems.

Handling Custom Status Codes and Errors

A good API should return meaningful HTTP status codes. Next.js allows you to customize responses easily.

Example:

You should also wrap database calls or external requests in try–catch blocks to handle errors gracefully. This improves reliability and provides clearer feedback to API consumers.

Security and Best Practices

When building API endpoints in Next.js, follow these best practices:

• Use TypeScript for type safety

• Validate input data with libraries like Zod or Yup

• Never expose secrets directly in code—use environment variables

• Keep endpoints focused on a single responsibility

• Handle errors consistently and return clear messages

• Secure sensitive routes with authentication and authorization

These practices are especially important when APIs are used in enterprise environments or integrated with ERP systems.

Why Next.js API Routes Matter

Next.js API routes reduce complexity by combining frontend and backend logic into a single project. This unified approach improves maintainability, speeds up development, and makes deployments easier.

For developers working with business systems, APIs built with Next.js can serve as powerful middleware between user interfaces and enterprise platforms, enabling modern, scalable solutions.

Conclusion

Building your first API endpoint in Next.js is a straightforward and rewarding process. With minimal setup, you can create powerful backend functionality that supports multiple HTTP methods, handles data securely, and integrates with databases and external services.

By mastering Next.js API routes, you gain the ability to build full-stack applications with clean architecture and modern best practices—an essential skill for today’s web developers and enterprise solution architects alike.

Book an implementation consultant today.