CodeIgniter 4 is a PHP full-stack web framework that emphasizes being lightweight, fast, flexible, and secure. It represents a complete rewrite of the framework to modernize the codebase and code quality while preserving the characteristics that made earlier versions popular.
The framework addresses the need for a structured, batteries-included approach to PHP web development. CodeIgniter 4 handles routing, database abstraction, templating, authentication, and other common web application concerns through built-in components. A key architectural change moves the index.php entry point into a public folder rather than the project root, improving security by preventing direct access to application logic and configuration files. Developers configure their web server to point to the public folder, keeping framework internals and business logic isolated from the web-accessible directory.
CodeIgniter 4 suits teams building traditional server-rendered web applications who value a lightweight framework with a shallow learning curve. It works well for projects where developers want convention-based structure without the complexity of heavier frameworks. The framework maintains backward compatibility with CodeIgniter 3 patterns where practical, though some components have been extracted into optional packages. The project distinguishes itself through its focus on simplicity and performance compared to more feature-heavy alternatives, though the README does not make explicit comparisons to other frameworks.
Development is entirely volunteer-driven, with the team requesting up to seven days for issue review and encouraging community contributions. The project uses GitHub issues strictly for bug reports and approved development work, directing feature requests and support questions to the forum to keep the issue tracker focused. Pull requests are welcomed when they address reported bugs or approved work packages, though unsolicited contributions are evaluated against the framework roadmap rather than accepted unconditionally. The team has accepted thousands of contributions since the framework's creation and actively solicits help across coding, documentation, and bug discovery.
