README

Need serverless backend? 
├─ Yes, for a static site → Pages Functions
├─ Yes, standalone API → Workers
└─ Just static hosting → Pages (no functions)

Have existing Worker?
├─ Complex routing logic → Use _worker.js (Advanced Mode)
└─ Simple routes → Migrate to /functions (File-Based)

Framework-based?
├─ Next.js/SvelteKit/Remix → Uses _worker.js automatically
└─ Vanilla/HTML/React SPA → Use /functions

/functions
  ├── index.js              → /
  ├── api.js                → /api
  ├── users/
  │   ├── index.js          → /users/
  │   ├── [user].js         → /users/:user
  │   └── [[catchall]].js   → /users/*
  └── _middleware.js        → runs on all routes

// /functions/users/[user].js
export function onRequest(context) {
  return new Response(`Hello ${context.params.user}`);
}
// Matches: /users/nevi

// /functions/users/[[catchall]].js
export function onRequest(context) {
  return new Response(JSON.stringify(context.params.catchall));
}
// Matches: /users/nevi/foobar → ["nevi", "foobar"]