I\'m working with API made from Django rest framework,
I am trying to make a filter to a JSON 
This is my  serializers.py file
from rest_framewo         
        For me, it works when I put the comma at the end of my filter_fields.
eg.
filter_fields = ('distribuidor',)
                                                                        it's also possible to supply your own Filter class, which may give you more options and flexibility
import sys, django_filters, json, io
class TaskFilter(django_filters.FilterSet):
    tag  = django_filters.CharFilter(name='tags__name', lookup_type='iexact')
    university = django_filters.NumberFilter(name='poster__university', lookup_type='exact')
    class Meta:
        model = Task
        fields = {
            'poster': ['exact'],
            'tasker': ['exact'],
            'status': ['exact'],
            'created': ['lt', 'gt']
        }
In this example I got filters
created__lt=2015-09-22 17:39:01.184681 (so I can filter datetime by values LESS THEN)
created__gt=2015-09-22 17:39:01.184681 (or GREATER THAN provided value)
Also I can hide foreign fields with custom filter fields, in this case it's tag & university. Plus I can provide comparison operator (lookup_type)
Sample request:
GET /api/v1/tasks/?offset=0&status=O&limit=100&university=1&ordering=-created&created__lt=2015-09-22 17:39:01.184681&tag=sport HTTP/1.1
Host: domain.com
Content-Type: application/json
Authorization: token 61cbd3c7c2656d4e24edb31f5923a86910c67b7c
User-Timezone: US/Pacific
Cache-Control: no-cache
                                                                        You need to define filter backend and all related fields you're planning to filter on:
class EstablecimientoViewSet(viewsets.ModelViewSet):
    filter_backends = (filters.DjangoFilterBackend,)
    filter_fields = ('categoria', 'categoria__titulo',)
example:
URL?categoria__titulo=Categoria 1