Challenges

Master AI-assisted coding through hands-on practice

33 challenges

6 categories

All Easy Medium Hard|Backend Frontend Incident Resolution DevOps Database AI Skills

Fix the Null Reference Bug

A REST API endpoint is crashing with a null reference error. Find and fix the bug that occurs when optional user data is missing.

Build a Todo API

Create a simple REST API for managing todos. Implement CRUD operations with the provided Express app skeleton.

Build a Rate Limiter

Implement a rate limiting middleware that limits requests per IP address. Start with the provided skeleton and complete the implementation.

Fix the Middleware Order

Authentication middleware is not protecting routes correctly. The order of middleware matters!

Fix the Async/Await Bug

An async function is not waiting for data to load before processing. Fix the promise handling issue.

The Shopping Cart Mystery

Customers are complaining about wrong totals in their shopping carts! Some orders show $NaN, others have incorrect amounts. Can you find the bugs before Black Friday?

The Mysterious Login Failures

DebugHardPremium

Users report intermittent login failures. The auth service works fine in development but fails randomly in production under load. Find and fix the race condition.