I used to use nock which would work very well in node environments. But this works in the browser as well. So I guess this can be fairly helpful while writing tests post development. If you are doing TDD, then recording/replaying doesn't fit anywhere in the development cycle.

I like the API of this library and the browser support that was missing in nock. So thanks Netflix! Although it would have been nice to see nock add this support. Which is what I wonder - why not just contribute to existing libraries.