Deploying Express Backend to Vercel

Tech Stack

• Node.js 16
• Express 4.18.2
• Vercel Serverless Functions

Introduction

Deploying web applications often demands a hosting platform that balances simplicity, scalability, and performance. In this post, we’ll walk you through how to deploy an Express.js backend to Vercel — a popular serverless platform — using a minimal setup. This approach works whether you're starting from scratch or transitioning an existing Node.js backend to a serverless environment.

Steps

1. Create the Express API

mkdir server
cd server
npm init -y
npm install express

Then create a file called app.js:

const express = require("express");
const app = express();
const PORT = 8000;
 
app.get("/", (req, res) => {
	res.send("Hello World");
});
 
app.get("/about", (req, res) => {
	res.send("About route");
});
 
app.listen(PORT, () => {
	console.log(`✅ Server is running on port ${PORT}`);
});

2. Add Vercel configuration

Create a vercel.json file at the root (or appropriate) level:

{
	"version": 2,
	"builds": [
		{
			"src": "app.js",
			"use": "@vercel/node",
			"config": { "includeFiles": ["dist/**"] }
		}
	],
	"routes": [
		{
			"src": "/(.*)",
			"dest": "app.js"
		}
	]
}

Also ensure your package.json has the start script:

{
	"name": "server",
	"version": "1.0.0",
	"main": "app.js",
	"scripts": {
		"start": "node app.js"
	},
	"dependencies": {
		"express": "^4.18.2"
	}
}

3. Push to GitHub

1. Initialize a git repository
2. Add files (git add .)
3. Commit (git commit -m "Initial commit")
4. Push to a GitHub repo

4. Connect to Vercel & Deploy

• Go to your Vercel dashboard
• “Import Project” → select your GitHub repo
• Vercel will automatically detect the project configuration and deploy your backend
• Once deployment completes, your backend will be live (e.g. https://your-project.vercel.app)

Notes & Considerations

• On Vercel, static assets should be placed in a public/ folder (rather than relying on express.static).
• If you prefer, you can also structure your project so the server entry is under /api — Vercel will treat files there as serverless functions.
• For more complex apps (e.g. database, environment variables, middleware), ensure all configs are properly set — Vercel’s serverless environment has constraints (function size, cold start, resource limits) to keep in mind.

Summary

Deploying an Express backend on Vercel can be quick and straightforward:

• Initialize a Node + Express project
• Configure vercel.json to let Vercel treat your app as a serverless function
• Push to GitHub, connect and deploy via Vercel

This approach helps you leverage serverless benefits — scalability, simplified deployment, and minimal infrastructure overhead.

Read the full article on Medium → Deploying Express Backend to Vercel