Architecting high-performance Route Handlers and backend logic in the App Router.
Next.js is a Fullstack Framework. Beyond rendering UI, it allows you to build custom HTTP endpoints using Route Handlers. These replace the legacy api/ routes from the Pages Router with a more robust, standard-compliant architecture.
External Access
When you need to provide an API for mobile apps, webhooks, or third-party services.
Legacy Integration
Handling complex HTTP methods (PUT, DELETE) or streaming non-HTML data.
Route Handlers are defined in route.ts files inside the app directory. They give you full control over the Request and Response objects.
import { NextResponse } from 'next/server';
export async function GET() {
const data = await fetchExternalData();
return NextResponse.json(
{ items: data },
{ status: 200 }
);
}export async function POST(request) {
const body = await request.json();
const { email, message } = body;
// Process data...
return NextResponse.json({ success: true });
}GET requests are cached by default unless they use dynamic functions like cookies() or headers().
import { cookies } from 'next/headers';
export async function GET(request) {
const cookieStore = await cookies();
const token = cookieStore.get('token');
// This route is now dynamic and NOT cached
return NextResponse.json({ authenticated: !!token });
}Server Actions are usually preferred for internal form submissions and database mutations. Route Handlers are for public or third-party API access.
"Use Route Handlers for resources. Use Server Actions for operations."
| Feature | Route Handlers | Server Actions |
|---|---|---|
| Standard HTTP | Full Control | Restricted |
| External Call | Yes (REST) | Internal only |
| CORS Support | Easy | Difficult |
| Usage | Third-party APIs | Forms / Mutations |
Route Handlers turn Next.js into a powerful distributed backend for modern digital products.
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