Hexagonal architecture is a software architecture that separates the business code from the application, its management (Web page, script, etc) and its infrastructure (database, services, etc).
This enables the core of the application to be isolated, develop it and test it independently. Another advantage is to also to be able to change the infrastructure if necessary without impacting the application's function. In practice, this means a system of intermediate layers between the application core code and other software layers. It groups all the models and business logic and enables a powerful modular structure when implementing as there is no link between the business code and the technical choices made.