Installing CodeIgniter

CodeIgniter 4 is distributed as a Composer project. Before starting, confirm that PHP 8.1 or newer is available and that the intl, mbstring, and json extensions are enabled.

Create the project

composer create-project codeigniter4/appstarter ci-app
cd ci-app
php spark serve

The development server listens on port 8080 by default. Open http://localhost:8080 and the CodeIgniter welcome page should appear.

Configure the environment

cp env .env

CI_ENVIRONMENT = development
app.baseURL = 'http://localhost:8080/'

In development you get detailed error pages and the debug toolbar. Switch to production only on the live server.

Connect a database

database.default.hostname = localhost
database.default.database = ci_app
database.default.username = app_user
database.default.password = secret
database.default.DBDriver = MySQLi

Keeping credentials in .env means the same codebase can run on a laptop, a staging server, and production.

Folder permissions

The writable directory must be writable by the web server. On Linux, use group ownership rather than permissive 777 permissions. On Windows, the default permissions normally work.

Useful spark commands

php spark routes
php spark make:controller Catalog
php spark make:model ProductModel
php spark make:migration CreateProducts
php spark migrate

If the page loads without styles, check that app.baseURL matches the address in your browser, including the trailing slash.