You can use either or both... server-side comes out of the box, and is used by the getting started tutorial. API-based is also very common using django-rest-fra

You can use either or both... server-side comes out of the box, and is used by the getting started tutorial. API-based is also very common using django-rest-framework. I'd say it is still a mix of both and both paths are well-supported and well-maintained.