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

The Event Emitter Memory Mystery

This Node.js application has a subtle memory behavior. Analyze the code and predict what will happen when processData is called 1000 times. Explain the memory implications.

Fix the Stale Closure

A counter component shows incorrect values due to a stale closure in the event handler. Fix the state management issue.

SEV1: Payment Service Outage

Critical incident: The payment service is down in production. Users cannot complete purchases. You are the on-call engineer - investigate the dashboards, logs, and traces to identify the root cause and determine the remediation steps.

The Cache Stampede Crisis

IncidentHardPremium

After a cache server restart, the database is being overwhelmed with requests. Diagnose the cache stampede and propose solutions.

Debug API Gateway Timeouts

Users are experiencing intermittent 504 timeout errors. Investigate the system to find the root cause and propose fixes.

Fix Connection Pool Exhaustion

DebugHardPremium

API requests are timing out. The database connection pool is being exhausted due to leaked connections.

Diagnose the Memory Leak

DebugHardPremium

Production servers are running out of memory. Analyze the code and logs to find the memory leak.

Fix Terraform State Issues

RefactorHardPremium

A Terraform configuration has state management problems causing conflicts in team environments. Fix the backend configuration.

E-commerce Checkout Security Review

Code ReviewHardPremium

Review this checkout system code for security vulnerabilities, data validation issues, and potential exploits. Document all issues you find.

Code Review: Security Audit

Code ReviewHard

Review this authentication code and identify all security vulnerabilities. Document your findings in the review.md file.

Analyze the Database Deadlock

Production transactions are failing with deadlock errors. Analyze the code to identify the deadlock pattern and propose a fix.

Fix the N+1 Query Problem

RefactorHardPremium

An API endpoint is making hundreds of database queries when it should only make one. Optimize the data fetching.

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.