CodeIgniter Tutorial

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CodeIgniter is a small-footprint, high-performance PHP MVC framework built for developers who want the structure of a framework without a heavy learning curve or a bloated runtime. This track covers CodeIgniter 4 (CI4), the current, actively maintained version, with a fully rewritten, namespaced codebase.

Where this fits: CodeIgniter is the easiest step up from Core PHP of all the frameworks on this site — its learning curve is gentle, its documentation is famously clear, and it stays out of your way far more than CakePHP or Symfony. Composer knowledge from the Composer track is helpful but not strictly required to get started.

Why "Lightweight"?

Compared to...	CodeIgniter's approach
CakePHP / Symfony	Smaller core, fewer abstractions, less "magic" — you can read and understand the whole request lifecycle quickly
A raw PHP script	Still gives you routing, an MVC structure, a Query Builder, and validation — no more reinventing the wheel
Modern frameworks in general	Runs comfortably on modest shared hosting, with minimal server requirements

A Quick Look Ahead

Example: A Minimal Controller

<?php

namespace App\Controllers;

class Articles extends BaseController
{
    public function show($id)
    {
        $model = new \App\Models\ArticleModel();
        $data['article'] = $model->find($id);
        return view('articles/show', $data);
    }
}

Note: This is correct, real CodeIgniter 4 code — but this website's own project doesn't have CodeIgniter installed, so you won't see it actually run on this page. Follow along in your own project after the next page's installation steps.

Why Learn CodeIgniter?

Reason	What it means for you
Gentle learning curve	One of the easiest MVC frameworks to pick up right after Core PHP
Fast and lightweight	Small core footprint means low overhead and quick page loads
Excellent documentation	Widely regarded as some of the clearest official docs in the PHP framework world
Still actively maintained	CodeIgniter 4 is a modern, namespaced, actively developed rewrite

Next steps: Head to Installation & Setup to create your first CodeIgniter 4 project via Composer.

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