🏢 Architecture Style vs. Architecture Pattern vs. Design Pattern

This content originally appeared on DEV Community and was authored by DevCorner

When designing software systems, understanding Architecture Styles, Architecture Patterns, and Design Patterns is crucial for scalability, maintainability, and efficiency. These concepts operate at different levels of abstraction. Let’s break them down!

1. Architecture Style

Definition

An Architecture Style defines the high-level structural pattern of a system, including how components interact and communicate.

Key Characteristics

• Scope: Entire system structure and behavior
• Purpose: Defines system-wide principles
• Focus: How components are structured and interact

Examples

• Monolithic Architecture
• Microservices Architecture
• Event-Driven Architecture
• Layered Architecture
• Service-Oriented Architecture (SOA)
• Client-Server Architecture

Analogy

Think of architecture style as a city plan—whether it’s a grid-based city, circular city, or a decentralized layout. It dictates the big-picture structure of the system.

2. Architecture Pattern

Definition

An Architecture Pattern provides a reusable solution to a common architectural problem within an architecture style. It describes how different components interact but is more specific than an architecture style.

Key Characteristics

• Scope: System-level but more specific than architecture styles
• Purpose: Solves a common architectural challenge using best practices
• Focus: Provides a structured solution within an architectural style

Examples

• Microservices Architecture Uses CQRS, Saga Pattern, API Gateway
• Layered Architecture Uses MVC (Model-View-Controller), MVVM (Model-View-ViewModel)
• Event-Driven Architecture Uses Pub-Sub Pattern, Event Sourcing

Analogy

If architecture style is a city plan, an architecture pattern is the design for road intersections, zoning rules, or how public transport is structured.

3. Design Pattern

Definition

A Design Pattern is a reusable code-level solution for solving common software design problems using object-oriented programming principles.

Key Characteristics

• Scope: Code level, applied to classes and objects
• Purpose: Improves reusability, maintainability, and scalability of code
• Focus: Best-practice solutions for software development

Categories & Examples

1. Creational Patterns (Object creation)

   • Factory Method
   • Abstract Factory
   • Builder
   • Singleton
   • Prototype

2. Structural Patterns (Object relationships)

   • Adapter
   • Decorator
   • Composite
   • Proxy
   • Facade

3. Behavioral Patterns (Communication between objects)

   • Observer
   • Strategy
   • Command
   • State
   • Template Method

Analogy

If architecture patterns are city zoning rules, design patterns are construction blueprints—how houses are structured (single-family, duplex, apartment buildings, etc.).

Key Differences

Example: Applying These Concepts Together

Scenario: You are designing an e-commerce system.

Step 1: Choose an Architecture Style

• You decide to use Microservices Architecture for scalability.

Step 2: Apply Architecture Patterns

• You implement an API Gateway Pattern to manage multiple microservices.
• You use CQRS (Command Query Responsibility Segregation) for handling product catalogs efficiently.

Step 3: Use Design Patterns in Implementation

• Use Factory Pattern to create different payment methods (Credit Card, PayPal, UPI).
• Use Observer Pattern to notify customers when their order status changes.
• Use Strategy Pattern to apply different discount calculation methods dynamically.

Conclusion

• Architecture Style defines the high-level system structure.
• Architecture Pattern provides best practices for structuring components.
• Design Pattern provides reusable code-level solutions for software development.

By understanding these concepts, you can design software systems that are scalable, maintainable, and efficient.

This content originally appeared on DEV Community and was authored by DevCorner