SOLID Principles

SOLID is a set of five design principles that help you write clean, maintainable, and scalable code.

Why do we need SOLID?

• Makes code easier to understand and change
• Reduces bugs
• Improves flexibility and scalability

Principles

• Single Responsibility Principle (SRP) — One responsibility.
• Open/Closed Principle (OCP) — Extend, don’t modify.
• Liskov Substitution Principle (LSP) — Subtypes must behave like base types.
• Interface Segregation Principle (ISP) — Don’t force unused methods.
• Dependency Inversion Principle (DIP) — Depend on abstractions.