System Design Concepts

Load Balancing

Distribute traffic across servers with algorithms like round-robin, least connections, and consistent hashing.

Database Scaling & Sharding

Partition data across multiple databases. Master range-based, hash-based, and directory-based sharding.

Caching Strategies

Speed up reads and reduce database load with caching layers — Redis, CDN, and application-level strategies.

Microservices vs Monolith

Break monoliths into independently deployable services. Trade-offs, patterns, and real-world architecture.

Message Queues & Event Streaming

Decouple services with asynchronous messaging. Kafka, RabbitMQ, and when to use each.

SQL vs NoSQL Databases

Choose between SQL and NoSQL. Know when relational consistency matters vs when you need flexible schemas.

Consistency & Replication

CAP Theorem

The fundamental theorem of distributed systems. Consistency, Availability, Partition Tolerance — pick two.

Fault Tolerance

High Availability

Rate Limiting & Throttling

Protect services from abuse. Token bucket, sliding window, and distributed rate limiting patterns.

Monitoring & Observability

Observe system health with metrics, logs, and traces. Build dashboards and alerting that catch issues before users do.

Security Fundamentals

Performance Optimization

API Design: REST vs GraphQL vs gRPC

Design clean APIs with REST, GraphQL, and gRPC. Know the trade-offs interviewers expect.

CDNs and Edge Computing

Serve content from edge locations worldwide. Reduce latency and offload origin servers.

Consistent Hashing

Distribute data evenly across nodes with minimal redistribution when nodes are added or removed.

Real-time Systems

System Design Patterns