Debug & Fix
Diagnose a real-looking bug, fix it, and explain the root cause in plain English. Tests debugging, code craft, and technical communication.
API Design
Design a small, minimal REST API for a real scenario. Tests resource modelling, scope judgment, and how you handle edge cases.
System Architecture Design
Design robust backends from the ground up. Tests component diagramming, scalability thinking, and trade-off analysis.
Database Modeling
Design robust relational schemas. Tests normalization, understanding of indexes, and planning for complex data relationships.
CI/CD Pipeline Setup
Design automated deployment workflows. Tests DevOps fundamentals, multi-environment setups, and zero-downtime deployment strategies.
Testing Strategies
Write robust automated tests. Tests unit testing pure functions, mocking databases for integration tests, and orchestrating E2E test flows.
Code Refactoring
Modernize and clean up legacy codebases. Tests SOLID principles, identifying code smells, and safely migrating logic.
Security Vulnerability Patching
Identify and fix critical security flaws. Tests OWASP Top 10 knowledge, sanitization, and preventing malicious injections.
Backend Performance Optimization
Speed up slow applications. Tests profiling, caching strategies (Redis), and mitigating N+1 query problems.
Asynchronous Processing
Manage long-running tasks and message queues. Tests event loops, worker threads, and distributed task queues (like RabbitMQ or BullMQ).
Authentication & Authorization
Secure user identities and permissions. Tests JWT lifecycles, OAuth flows, and Role-Based Access Control (RBAC).
Containerization & Orchestration
Deploy applications reliably at scale. Tests Docker best practices, multi-container Compose setups, and Kubernetes fundamentals.