What are route handlers vs API routes in App Router?

In the App Router, API routes are now called "Route Handlers" and use the route.js file convention instead of the pages-based approach.

Pages Router (API Routes):

pages/api/users.js

App Router (Route Handlers):

app/api/users/route.js
jsx
// app/api/users/route.js
export async function GET(request) {
  const users = await getUsers();
  return Response.json(users);
}

export async function POST(request) {
  const data = await request.json();
  const user = await createUser(data);
  return Response.json(user, { status: 201 });
}

export async function PUT(request) {
  const data = await request.json();
  const user = await updateUser(data);
  return Response.json(user);
}

export async function DELETE(request) {
  await deleteUser(request.nextUrl.searchParams.get("id"));
  return new Response(null, { status: 204 });
}

Route handlers support all HTTP methods and provide better TypeScript support and Web APIs compatibility.