# SOLID Principles

Five guidelines for keeping object-oriented code easy to change.

## What is **SOLID Principles**?

**SOLID** is five guidelines for keeping object-oriented code easy to change: **S**ingle responsibility, **O**pen/closed, **L**iskov substitution, **I**nterface segregation and **D**ependency inversion.

Level: Freelancer · [More OOP terms at this level](https://www.ask-codey.com/glossary/subjects/oop/freelancer)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/solid-principles