Setting up a new Node.js + Express backend project from scratch — folder structure, package.json, and initial config.

Project Setup

This is the starting point for every backend project in this section — the folder structure and config files we build on for schemas, auth, and everything else.

Initialize the Project

mkdir my-app-backend
cd my-app-backend
npm init -y

Install the core packages every backend needs:

npm install express mongoose dotenv cors
npm install -D nodemon

express — the web server framework
mongoose — MongoDB connection and schemas
dotenv — load environment variables from .env
cors — allow the frontend to talk to this backend
nodemon — auto-restarts the server on file changes (dev only)

Folder Structure

This is the standard structure used across this entire section — every file we write later goes in one of these folders.

my-app-backend/
├── src/
│   ├── config/
│   │   └── db.js              # MongoDB connection
│   ├── models/
│   │   ├── user.model.js
│   │   └── post.model.js
│   ├── controllers/
│   │   ├── auth.controller.js
│   │   └── post.controller.js
│   ├── routes/
│   │   ├── auth.routes.js
│   │   └── post.routes.js
│   ├── middleware/
│   │   ├── auth.middleware.js
│   │   └── error.middleware.js
│   ├── utils/
│   │   └── asyncHandler.js
│   └── app.js                 # Express app setup
├── server.js                  # entry point
├── .env
├── .env.example
├── .gitignore
└── package.json

mkdir -p src/config src/models src/controllers src/routes src/middleware src/utils

package.json — Scripts

Open package.json and add a type and scripts section:

{
  "name": "my-app-backend",
  "version": "1.0.0",
  "type": "module",
  "main": "server.js",
  "scripts": {
    "dev": "nodemon server.js",
    "start": "node server.js"
  },
  "dependencies": {
    "cors": "^2.8.5",
    "dotenv": "^16.4.5",
    "express": "^4.21.0",
    "mongoose": "^8.7.0"
  },
  "devDependencies": {
    "nodemon": "^3.1.7"
  }
}

"type": "module" enables ES module syntax — import/export instead of require/module.exports. This is the modern standard and what every file in this section uses.

.env and .env.example

# .env — your actual secrets, never committed to git
PORT=5000
MONGO_URI=mongodb+srv://username:password@cluster.mongodb.net/myapp
JWT_SECRET=your_super_secret_key_here
JWT_REFRESH_SECRET=another_super_secret_key
NODE_ENV=development
CLIENT_URL=http://localhost:5173

# .env.example — committed to git, shows what variables are needed
PORT=5000
MONGO_URI=
JWT_SECRET=
JWT_REFRESH_SECRET=
NODE_ENV=
CLIENT_URL=

.env.example has no real values — it just documents what environment variables the project needs. Anyone cloning the repo copies it to .env and fills in their own values.

.gitignore

# .gitignore
node_modules/
.env
.DS_Store
*.log
dist/
build/

Never commit node_modules or .env — the first is huge and reproducible, the second contains secrets.

Verify the Setup

Create a minimal server.js just to confirm everything works — we replace this properly in the next file.

// server.js
import express from "express";

const app = express();
const PORT = process.env.PORT || 5000;

app.get("/", (req, res) => {
  res.send("Server is running");
});

app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

npm run dev

Visit http://localhost:5000 — you should see "Server is running".

This server.js is temporary. The next file — Server Setup — replaces it with the real structure: app.js for Express configuration and server.js as a thin entry point that connects to MongoDB before starting the server.

Summary

npm init -y then install express mongoose dotenv cors plus nodemon as a dev dependency
"type": "module" in package.json enables modern import/export syntax
Standard folder structure — config, models, controllers, routes, middleware, utils
.env holds real secrets — never committed — .env.example documents what's needed
npm run dev starts the server with auto-restart via nodemon
Next file connects this setup to MongoDB and builds out the real app.js

Project Setup

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