The RestAPI is the major communication interface between backend and frontends like web client, or native apps. The RestAPI is described using OpenAPI and rendered by swagger-php. That way developers can see all available API endpoints documented nicely.
📄️ Usage for implementation
The implementation of an RestAPI endpoint action typically starts with a RestAPI description with annotations for Swagger-php integrated by Symfony via NelmioApiDocBundle followed by FOSBundle endpoint type description.