Node Backends on Vercel

Vercel supports Node.js backend frameworks as first-class apps. Express and Hono are the most common, but Fastify, Elysia, NestJS, H3, and Koa are also supported. Your app is the entrypoint — not the api/ folder. No rewrites, no build scripts. Just export your app and deploy.

Quick Start

# Express
npm init -y && npm i express
# Create server.ts that exports default app
vc dev       # local development
vc deploy    # deploy

How It Works

1. Vercel detects the framework from package.json dependencies
2. Finds your entrypoint file (must import the framework)
3. Introspects your routes automatically — no vercel.json rewrites needed
4. Bundles and deploys as a single Lambda

Entrypoint Detection

Vercel searches for these filenames (in order): app, index, server, main, src/app, src/index, src/server, src/main

With these extensions: .js, .cjs, .mjs, .ts, .cts, .mts

The preferred entrypoint filename is server.ts. The file must import the framework (import express from 'express', import { Hono } from 'hono', etc.).

We recommend using export default for the app instance, but calling .listen() also works.

Minimal Express App

my-app/
├── package.json
└── server.ts

package.json:

{
  "type": "module",
  "dependencies": {
    "express": "5.1.0"
  }
}

server.ts:

import express from 'express';

const app = express();

app.get('/', (_req, res) => {
  res.send('Hello Express!');
});

export default app;

Minimal Hono App

package.json:

{
  "type": "module",
  "dependencies": {
    "hono": "^4.8.9"
  }
}

server.ts:

import { Hono } from 'hono';

const app = new Hono();

app.get('/', c => {
  return c.text('Hello Hono!');
});

export default app;

Local Development

Run vc dev from the project root. Vercel runs your app directly with TypeScript support. No dev script is required, though you can add one if you prefer.

Static files in public/ are served automatically.

Configuration

Most apps need zero configuration. Optional vercel.json settings:

{
  "functions": {
    "server.ts": {
      "includeFiles": "views/**/*"
    }
  }
}

Anti-Patterns

• Putting routes in api/ folder: Your framework IS the app. Define routes in your app code, not as separate files in api/.
• Adding vercel.json rewrites: Routes are introspected automatically from your app. Rewrites are not needed.
• Adding a build script: Vercel handles TypeScript compilation and bundling. Don't add a build script for transpilation — it's not needed and can cause issues.