Checklist

• I have verified that that issue exists against the master branch of Django REST framework.
• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to the discussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to be in the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

import numpy as np
from rest_framework.response import Response
analisys = {'raw_images': np.NaN}
return Response(analisys, status=200, content_type='application/json')

Expected behavior

I expected what response body is

{"raw_images": null}

Actual behavior

I get this invalid json and i cannot handle this response in JS

{"raw_images": NaN}