Discover how Next.js 15 App Router and Route Handlers redefine the way we build fullstack APIs — from streaming responses to edge-ready endpoints.
Carlos Ruiz
Lead Engineer
The App Router introduced a fundamentally different model for building server-side logic in Next.js. With Route Handlers, you define API endpoints as co-located files alongside your pages, and you get the full power of Web APIs without any Node.js-only abstractions.
The old pages/api system was a thin wrapper over Node.js HTTP. Route Handlers, by contrast, are built on the Fetch API's Request and Response types. That means they run natively on the Edge, in serverless environments, and locally — all with the same code.
One of the most powerful features is first-class streaming support. You can return a ReadableStream directly, enabling real-time data delivery to your frontend.
export async function GET() {
const stream = new ReadableStream({
start(controller) {
controller.enqueue('data: hello
');
controller.close();
},
});
return new Response(stream, {
headers: { 'Content-Type': 'text/event-stream' },
});
}Route Handlers participate in the same caching system as Server Components. Use export const revalidate = 60 to cache responses for 60 seconds, or export const dynamic = 'force-dynamic' for always-fresh data.
Carlos Ruiz
Lead Engineer at Lamio
Expert in modern software engineering with a focus on scalable architectures, performance optimization, and developer experience.
Generics are the most powerful feature in TypeScript that most developers underuse. Once you internalize them, you'll write fundamentally safer abstractions.
Carlos Ruiz
Mar 14, 2026
Get the latest engineering insights, tutorials, and tech updates from the Lamio team.
No spam, ever. Unsubscribe at any time.