🛠️ Node.js Backend Setup

Time to build your AI backend! 🚀

We’ll use Node.js with Express. It’s straightforward, reliable, and works with any frontend—React, Vue, mobile apps, or browser extensions. This setup gives you full control over your server and is easy to adapt for production.

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💡 Why Not Just Use Next.js?

Next.js is great for building websites and small APIs. But for AI apps, especially those running in production, a dedicated backend can save you a lot of headaches.

Here’s why:

• Serverless timeouts: Large AI jobs (like processing big prompts or files) can exceed serverless limits.
• Real-time features: Audio, video, and long-running AI tasks work better with a traditional backend.

💡 You can always switch to Next.js later if you want its frontend features, but starting with Express keeps things simple and reliable.

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📁 Step 1: Create Your Project

Let’s set up your workspace:

mkdir openai-backend
cd openai-backend
npm init -y

Now create your environment and ignore files:

touch .env
echo "node_modules/" > .gitignore
echo ".env" >> .gitignore

✅ This creates a Node project and ensures your secrets won’t end up in Git.

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📦 Step 2: Install Dependencies

Core packages:

npm install express cors dotenv openai

Development tools:

npm install -D nodemon

What each package does:

• express → Your web server (handles HTTP requests)
• cors → Lets your frontend connect to your backend
• dotenv → Loads your API keys from .env securely
• openai → Official OpenAI JavaScript client
• nodemon → Auto-restarts the server when files change

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⚙️ Step 3: Configure Modern JavaScript

Update your package.json to enable modern syntax:

{
  "name": "openai-backend",
  "version": "1.0.0",
  "type": "module",
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js"
  }
}

💡 The "type": "module" line lets you use import instead of require().

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🔑 Step 4: Add Your API Key

Open .env and add your OpenAI API key:

OPENAI_API_KEY=sk-proj-your-actual-key-here
PORT=8000

Replace sk-proj-your-actual-key-here with your real API key from the previous lesson.

⚠️ Never commit .env to Git — your .gitignore already protects it.

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🛠️ Step 5: Create Your Server

Make a file called index.js:

import express from "express";
import { config } from "dotenv";
import cors from "cors";

// Load environment variables
config();

const app = express();
const PORT = process.env.PORT || 8000;

// Middleware
app.use(cors()); // Allow frontend connections
app.use(express.json()); // Parse JSON requests

// Test route
app.get("/", (req, res) => {
  res.json({
    message: "🤖 OpenAI Backend is running!",
    status: "ready"
  });
});

// Start server
app.listen(PORT, () => {
  console.log(`🚀 Server running on http://localhost:${PORT}`);
  console.log(`📚 Ready for OpenAI integration!`);
});

What this does:

• Starts an Express server on port 8000
• Enables CORS so your frontend can talk to it
• Automatically parses JSON requests
• Adds a simple test route to confirm it’s working

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🧪 Step 6: Test Your Server

Run:

npm run dev

✅ You should see:

🚀 Server running on http://localhost:8000
📚 Ready for OpenAI integration!

Test in your browser: http://localhost:8000
You should see:

{
  "message": "🤖 OpenAI Backend is running!",
  "status": "ready"
}

Or test in your terminal:

curl http://localhost:8000

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🔧 Troubleshooting

❌ “Cannot use import statement”
✅ Add "type": "module" to package.json.

❌ “Port 8000 already in use”
✅ Change PORT=8001 in .env.

❌ “command not found: npm”
✅ Install Node.js from nodejs.org.

❌ “Cannot find module ‘express’”
✅ Run npm install again in the correct folder.

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📂 Project Structure

openai-backend/
├── index.js          # Main server file
├── package.json      # Project config
├── .env              # API keys (private)
├── .gitignore        # Protects secrets
└── node_modules/     # Dependencies

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🎉 Your backend is now ready for AI integration.

Next: Your First AI Endpoint — time to give your server some brainpower!