So far, you have learned how to build pages and collect user input. However, real applications also need a way to process data on the server.

For example:

• Saving form data;
• Handling requests;
• Working with APIs.

In Next.js, this is done using Route Handlers.

Route Handlers allow you to create backend logic directly inside your Next.js project, without needing a separate server.

Creating a Route Handler

Route Handlers are created inside the app/api/ folder.

Example:

app/
  api/
    contact/
      route.ts

Example: Basic Route Handler

export async function POST(request: Request) {
  const data = await request.json();

  return Response.json({
    message: "Data received",
    data,
  });
}

This function handles POST requests sent to:

/api/contact

How It Works

When a request is sent to /api/contact, Next.js runs this function on the server.

You can define different handlers based on HTTP methods:

• GET: retrieve data;
• POST: send data;
• PUT: update data;
• DELETE: remove data.

Each method is a separate exported function.

Example - GET Handler

export async function GET() {
  return Response.json({ message: "Hello from API" });
}

Why Route Handlers Are Useful

Route Handlers allow your app to handle backend logic directly.

This means you can:

• Process form submissions;
• Connect to databases;
• Build APIs;
• Handle authentication logic.

All of this can be done inside the same project.