What are Route Handlers in Next.js and how do they differ from Pages API routes?

// app/api/todos/route.ts
import { NextResponse } from 'next/server';

export async function GET() {
  return NextResponse.json(await db.todo.findMany());
}
export async function POST(request: Request) {
  const body = await request.json();
  const todo = await db.todo.create({ data: body });
  return NextResponse.json(todo, { status: 201 });
}