CodeIgniter is an open-source web application framework for building dynamic web applications using PHP. It was created by EllisLab and is now maintained by the CodeIgniter Foundation. CodeIgniter is known for its simplicity, speed, and small footprint compared to other PHP frameworks. It follows the Model-View-Controller (MVC) architectural pattern and provides a variety of features and libraries to streamline web development.Here are some key features and characteristics of CodeIgniter:MVC Architecture: CodeIgniter encourages developers to separate their application logic into three components: Models (for data handling and business logic), Views (for presentation and user interface), and Controllers (for managing the flow of the application).Lightweight: CodeIgniter is known for its small footprint. It doesn't require a vast amount of server resources and can be run on most hosting environments with minimal configuration.