CodeIgniter 4 is a lightweight and powerful PHP framework designed for developers who want speed, simplicity, and performance.
It follows modern PHP standards while remaining easy to learn, making it a great choice for small to medium-sized web applications.
In this guide, you’ll learn how to install CodeIgniter 4 step by step using the recommended methods.
Prerequisites for Installing CodeIgniter 4
Before installing CodeIgniter 4, ensure your system meets the following requirements:
- PHP (version 8.1 or higher recommended)
- Composer
- Web server (Apache or Nginx)
- Database (MySQL / MariaDB)
Check PHP Version
php -v
Step 1: Install Composer
Composer is required to install and manage CodeIgniter 4 dependencies.
Download Composer
php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
Install Composer Globally
php composer-setup.php --install-dir=/usr/local/bin --filename=composer
Verify installation:
composer -V
Step 2: Install CodeIgniter 4 Using Composer
Create a New Project
composer create-project codeigniter4/appstarter myapp
This command:
- Downloads CodeIgniter 4
- Sets up the project structure
- Installs required dependencies
Move into the project directory:
cd myapp
Step 3: Configure Environment File
Copy the example environment file:
cp env .env
Open .env and update:
CI_ENVIRONMENT = development
Step 4: Set Application Base URL
Edit .env:
app.baseURL = 'http://localhost:8080/'
Setting the base URL helps with routing and asset loading.
Step 5: Configure Database Connection
Update database settings in .env:
database.default.hostname = localhost
database.default.database = myapp_db
database.default.username = myapp_user
database.default.password = your_password
database.default.DBDriver = MySQLi
Step 6: Run CodeIgniter 4 Development Server
Start the built-in server:
php spark serve
Open in browser:
http://localhost:8080
You should see the CodeIgniter 4 welcome page 🎉
Alternative Method: Manual Installation (ZIP)
- Download the latest CodeIgniter 4 from the official website
- Extract files into your web directory
- Configure
.envand base URL - Set permissions for writable folder
⚠️ Composer installation is strongly recommended for updates and security.
Common Issues & Fixes
1. Writable Directory Permission Error
chmod -R 775 writable
2. Missing PHP Extensions
Install:
php-intl php-mbstring php-curl php-xml
3. Base URL Not Working
Make sure app.baseURL matches your server URL exactly.
Why Choose CodeIgniter 4?
CodeIgniter 4 is preferred because:
- Lightweight and fast
- Simple learning curve
- Modern PHP standards
- Minimal configuration
- Excellent performance
It’s ideal for small projects, APIs, and high-performance apps.
Final Thoughts
Installing CodeIgniter 4 is quick and straightforward, especially using Composer.
If you prefer a lightweight framework with flexibility and speed, CodeIgniter 4 is an excellent choice.
