URL Shortener and Rate Limiter Design

Indexes, Query Patterns, and Storage Performance

Medium-hard practice on index design, query access patterns, write costs, pagination, and performance troubleshooting.

Sync vs Async Architecture Decisions

Medium-hard practice on request paths, queues, events, workflows, user feedback, and delayed consistency trade-offs.

Failover, Disaster Recovery, and Backups

Medium-hard practice on failover strategy, RPO, RTO, backups, restore testing, multi-region recovery, and disaster readiness.

SQL, NoSQL, and Data Modeling Decisions

Medium-hard practice on choosing relational, document, key-value, graph, and wide-column models for system-design workloads.

Timeouts, Retries, and Circuit Breakers

Medium-hard practice on failure handling, timeout budgets, retry safety, circuit breakers, and dependency protection.

Monolith, Microservices, and Modular Boundaries

Medium-hard practice on when to keep a monolith, split services, define ownership, and manage modular boundaries.

Scalability Patterns and Bottlenecks

Medium practice on finding bottlenecks, choosing scaling patterns, and reasoning about capacity under load.

Caching, Queues, and Read Scaling

Medium practice on cache strategy, asynchronous processing, replicas, read models, and stale-data trade-offs.