CodeIgniter is an open-source web application framework for building dynamic websites using PHP. It's known for its simplicity, speed, and a small footprint compared to other PHP frameworks.
It organizes code into models (for data handling), views (for user interface), and controllers (for application logic), making the development process more organized and maintainable.
It offers a rich set of libraries for various common tasks, such as database manipulation, form validation, sessions, encryption, and more. These libraries reduce the need for writing repetitive code from scratch.