Wrong answer @dkayiwa!
@shivtej, what you're really asking is what is the most efficient way to test that the small iterative changes you make to your code have the behaviors that you want. The right answer to this is not "hot reloading", it's Test Driven Development.
Basically, (1) you write a a test expressing the behavior that you want your REST API to have, then (2) you write the code to implement this behavior, (3) running the test each time you make a change to ensure you've got it right.
If you're not familiar with TDD and/or you haven't done it before, I can 100% guarantee you that learning to do TDD while you build this REST API will save you time, even on the first project, versus running this code on a live server (and reloading it a lot) and manually testing it.