API Server (Backend)

If the REST API is the menu, the API Server is the Chef. It is a program (usually running 24/7) that listens for incoming requests, runs logic, connects to the database, and sends a response.

🏗️ Anatomy of a Server

1. The Listener

The server binds to a Port (like 3000 or 8080) and waits forever. It's like a receptionist sitting at the desk waiting for the phone to ring.

2. Middleware

The security guards. Before the request reaches the main logic, it passes through layers: Logging, Authentication, Body Parsing, Rate Limiting.

3. The Controller

The brain. Once the request passes the guards, the Controller decides what to do (e.g., "Find user ID 5 in DB") and sends the JSON response.

🕹️ The Middleware Gauntlet

Mission: Configure your Express.js server stack.
Enable the right Middleware to stop the Hacker (👾) while letting the User (👤) access the database.

Server Configuration

Auth Middleware

Verify API Key / Token

Rate Limiter

Block spamming IPs

const app = express();

// Middleware Stack
// ...

app.get('/data', (req, res) => {
  db.findData();
});
        

🌐

⏱️

Rate Limit

🔐

Auth

🧠

Logic

🗄️

> Server listening on port 3000...