Low-Level Design
LLD focuses on the internal structure of components: classes, interfaces, relationships, and design patterns that make code maintainable and extensible.
Foundations
Section titled “Foundations”- SOLID Principles — The five pillars of object-oriented design
- UML Design — Class diagrams, sequence diagrams, and visual modeling
Design Principles
Section titled “Design Principles”- Design Principles — DRY, KISS, YAGNI, Separation of Concerns
- Design Principles II — Law of Demeter, Boy Scout Rule, Coupling vs Cohesion
Design Patterns
Section titled “Design Patterns”- Creational Patterns — Factory, Builder, Singleton, Prototype
- Structural Patterns — Adapter, Decorator, Facade, Proxy, Composite
- Behavioral Patterns — Observer, Strategy, Command, State, Template Method
- Pattern Cheat Sheet — Quick reference and decision flowchart
API Design
Section titled “API Design”- API Design Guidelines — RESTful conventions, naming, versioning, and error handling