What Are Design Patterns in Software Engineering

Short answer

Design patterns are reusable solutions to common software design problems. They provide shared vocabulary and proven templates for object-oriented design.

How it works

Patterns are categorized as creational, structural, and behavioral. Examples include Singleton, Factory, Observer, and Strategy. They are not copy-paste code but adaptable concepts.

Example

The Observer pattern lets objects subscribe to events. When data changes, all subscribers are notified automatically, as in React's state management.

Why it matters

Patterns reduce technical debt and improve communication among developers. They encapsulate decades of collective experience into actionable guidelines.