System Design Patterns
System Design Patterns
System design is the process of defining the architecture, components, and data for a system to satisfy specified requirements. It’s about scalability, availability, and resilience.
🏗️ 1. Microservices Architecture
Break down a large monolithic application into small, independent services that communicate via lightweight protocols (e.g., HTTP/REST or gRPC).
- Benefits: Independent deployment, technology diversity, and fault isolation.
- Challenges: Increased complexity in inter-service communication and data consistency.
🚀 2. Event-Driven Architecture (EDA)
Services communicate by producing and consuming events asynchronously. This is the foundation of highly decoupled systems.
- Pub/Sub Pattern: A producer sends a message to a topic, and multiple consumers receive it.
- Message Queues: Used for point-to-point communication and task leveling.
📊 3. CQRS (Command Query Responsibility Segregation)
Separate the models for reading data from the models for writing (updating) data.
- Command Side: Optimized for data consistency and business logic.
- Query Side: Optimized for read performance, often using a read-optimized database (like Redis or Elasticsearch).
🛠️ 4. API Gateway Pattern
A single entry point for all client requests. It handles authentication, rate limiting, and request routing to various microservices.
- BFF (Backend for Frontend): A variation where separate gateways are created for mobile, web, and external APIs.
📉 5. Circuit Breaker
Prevent a failure in one service from cascading to others. If a service call fails repeatedly, the circuit “trips,” and subsequent calls return an error immediately without wasting resources.
💡 Summary Table
| Pattern | Best For | Main Tradeoff |
|---|---|---|
| Microservices | Scalable, large teams | High operational overhead |
| Event-Driven | Decoupling, real-time | Complexity in tracing events |
| CQRS | Read/Write heavy apps | Data eventual consistency |
| API Gateway | Security, complexity management | Single point of failure (if not HA) |
| Serverless | Sporadic, event-based tasks | ”Cold start” latency |