Can you describe a backend system you developed from scratch?

fastqa

Sure, I can walk you through a backend system I built from scratch.

Overview

I developed a RESTful API for an e-commerce application. The system was designed to handle user authentication, product management, and order processing.

Key Components

1. Authentication

Utilized JWT (JSON Web Tokens) for secure user authentication.
Implemented OAuth 2.0 for third-party login options.

2. Database

Used PostgreSQL for relational data storage.
Designed database schemas to handle user data, product catalogs, and order details.

3. API Endpoints

Created endpoints for CRUD operations on products and orders.
Implemented pagination and filtering to handle large datasets efficiently.

4. Middleware

Added middleware for logging, error handling, and request validation using Express.js.

Code Snippet

const express = require('express');
const jwt = require('jsonwebtoken');
const app = express();

// Middleware for JWT Authentication
app.use((req, res, next) => {
  const token = req.header('Authorization');
  if (!token) return res.status(401).send('Access Denied');
  try {
    const verified = jwt.verify(token, process.env.TOKEN_SECRET);
    req.user = verified;
    next();
  } catch (err) {
    res.status(400).send('Invalid Token');
  }
});

// Example Endpoint
app.get('/api/products', (req, res) => {
  // Logic to fetch products from database
  res.send(products);
});

app.listen(3000, () => console.log('Server running on port 3000'));

Challenges and Solutions

Scalability: Implemented caching using Redis to reduce database load.
Security: Used Helmet.js to secure HTTP headers and prevent common vulnerabilities.

Conclusion

This backend system was designed with a focus on scalability, security, and maintainability. It successfully handled high traffic and provided a robust foundation for the e-commerce application.

FastQA