I don't use Django but I use Ruby on Rails, and turning a server-side rendered page into an API is trivial. Rails requests automatically understand the format of a request and let you specify what do when a specific kind of format comes in: ie. when it's an html request, render this page, when it's a "js" request, render a jbuilder template. ezpz
whatever frontend framework you're using has really nothing to do with it at all.