Your roadmap to real skills.

What System Design Is and Why It Matters

Explain system design, the questions senior engineers ask, and the four building blocks of any system.

Scalability Fundamentals and CAP Theorem

Distinguish vertical vs horizontal scaling, stateless vs stateful, and reason about CAP and PACELC.

Databases at Scale

Apply read replicas, connection pooling, and sharding to scale a database past single-instance limits.

Caching

Apply cache-aside vs write-through patterns, design invalidation, and choose between Redis, CDN, and DB caches.

Load Balancing

Pick between round-robin and least-connections, design health checks, and implement graceful shutdown.

Message Queues and Async Processing

Decide when to introduce a queue and pick from Redis/RabbitMQ/SQS/Kafka for a specific workload.

Designing a Real System (URL Shortener, Notifications, Twitter Feed)

Walk through three canonical system-design problems end-to-end with the building blocks from earlier lessons.

Rate Limiting

Apply token bucket and leaky bucket algorithms and decide where in the stack to enforce limits.

Microservices vs Monolith

Compare microservices vs monolith honestly, identify when each fits, and avoid the cargo-cult adoption pattern.

API Design: REST vs GraphQL vs gRPC

Choose between REST, GraphQL, and gRPC, and design versioning, pagination, and idempotency correctly.

Reliability and Fault Tolerance

Reason about SLIs/SLOs/SLAs and design retries with backoff, circuit breakers, and graceful degradation.

System Design Interview Job Readiness

Structure a 45-minute system design interview and communicate tradeoffs to land mid-to-senior engineering offers.