SOLID Principles

Five principles for building software that is easy to understand, extend, and maintain. They reduce coupling, increase cohesion, and make code testable.

When to Apply

Reference these principles when:

• Designing new classes, modules, or interfaces
• Refactoring code with too many responsibilities
• Reviewing PRs for architectural concerns
• Breaking apart god objects or fat interfaces
• Deciding where to draw module boundaries
• Making code more testable

Quick Reference

| Principle | One-Liner | Red Flag |