What is CodeIgniter 4 modular architecture patterns?
Why Interviewers Ask This
Senior CodeIgniter engineers are expected to reason about architecture, performance, and edge cases. This question separates mid-level from senior candidates by testing deep system-level understanding.
Answer
Building a modular CI4 application involves organizing code into self-contained feature modules. Register module namespaces in app/Config/Autoload.php: $psr4 = ["App" => APPPATH, "Modules\Blog" => ROOTPATH . "modules/Blog", "Modules\Auth" => ROOTPATH . "modules/Auth"]. Each module has its own directory: modules/Blog/Controllers/, models/, Views/, Config/, Database/Migrations/. Routes: include module routes in the main routes file: require ROOTPATH . "modules/Blog/Config/Routes.php". Config: module config files are auto-discovered if they extend BaseConfig. Module migrations: php spark migrate --namespace=Modules\Blog. This architecture improves code organization and allows modules to be enabled/disabled by adding/removing the namespace registration. The modular pattern is especially valuable for large teams where different teams own different feature modules.
Common Mistake
Candidates often give textbook answers here. Interviewers are more impressed when you relate the concept to a specific problem you solved in a real CodeIgniter project.