rest_framework.utils.html.is_html_input() combined withrest_framework.utils.html.parse_html_dict() does not detect 3+ level dictionaries, for example.

1. Multipart representation of{'a':{'b':{'c':123}}} isQueryDict([('a.b.c',123)]), sois_html_input() properly detects nested dictionary.
2. On the second pass there is{'b.c':123} andis_html_input() does not detect the nested dictionary.

My suggestion is to either instantiate or returnMultiValueDict instead of simpledict inparse_html_dict() (and possiblyparse_html_list())
https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/utils/html.py