I've a React.js application which depends on an API (based on Django Rest Framework).
The React and Django applications are decoupled i.e in my local development environment, I run two servers (each using a different port), one for Django and the other for the React.
Is it possible to deploy this to a single heroku application or will I need two separate applications?
You can use the same heroku instance if you serve the static React files from the Django app, perhaps in the public directory. Tell the Django app to respond to GET requests to / by delivering the main React html page.