Common Software Architecture Patterns: Layered, Multi‑Layer, Pipe‑Filter, Client‑Server, MVC, Event‑Driven, and Microservices

Software architecture patterns provide reusable solutions to common design problems; this article introduces seven major patterns.

1. Layered Architecture – also called n‑tier, typically consists of presentation, business, persistence, and database layers, emphasizing separation of concerns, but may introduce performance overhead and increased complexity.

2. Multi‑layer Architecture – similar to layered but applied in distributed systems, grouping components into logical layers; benefits and drawbacks are comparable.

3. Pipe‑Filter Architecture – processes data through a series of filters (producer, transformer, tester, consumer); suitable for data‑flow or ETL tasks, but less ideal for interactive systems.

4. Client‑Server Architecture – separates requesters (clients) and providers (servers); useful for web, email, or banking services, yet can create performance bottlenecks and single points of failure.

5. Model‑View‑Controller (MVC) – divides applications into model, view, and controller components; widely used for web and mobile UI, though may be overkill for simple interfaces.

6. Event‑Driven Architecture – handles asynchronous events with independent processors; scalable but may face performance and error‑recovery challenges.

7. Microservices Architecture – decomposes applications into independently deployable services with their own APIs and databases; offers scalability and language heterogeneity, yet adds operational complexity and monitoring overhead.

Example code snippets illustrate event handling in a microservices context, such as creating an OrderCreated event and processing it with CreditReserved or CreditLimitExceeded events.