CodeIgniter Knowledge Base

Quick reference for CodeIgniter 4 framework patterns and PHP implementation guidelines. CodeIgniter 4 is a complete rewrite of the framework, built for PHP 8.1+ with namespaces, autoloading, and a modern MVC architecture. It remains lightweight and fast while providing the tools needed for professional application development.

Core Principles

MVC Architecture

Request → index.php → Bootstrap → Routing
  → Filters (before) → Controller → Service/Model → View
  → Filters (after) → Response