DRF Filtering, Ordering & Pagination: Building Fast Search APIs

An API endpoint returning 100,000 unpaginated records will crash your database and overwhelm client devices with massive JSON payloads. DRF provides robust tools to paginate, filter, and sort results efficiently.

Configuring Advanced Filtering with django-filter

# Install django-filter
pip install django-filter

Define a dedicated FilterSet with custom lookups:

# blog/filters.py
import django_filters
from .models import BlogPost

class BlogPostFilter(django_filters.FilterSet):
    min_price = django_filters.NumberFilter(field_name="premium_price", lookup_expr='gte')
    max_price = django_filters.NumberFilter(field_name="premium_price", lookup_expr='lte')
    category_slug = django_filters.CharFilter(field_name="category__slug", lookup_expr='iexact')

    class Meta:
        model = BlogPost
        fields = ['category_slug', 'is_published', 'min_price', 'max_price']

Attaching Filters and Pagination to ModelViewSet

# blog/views.py
from rest_framework import viewsets, filters
from django_filters.rest_framework import DjangoFilterBackend
from .models import BlogPost
from .serializers import BlogPostSerializer
from .filters import BlogPostFilter

class BlogPostViewSet(viewsets.ModelViewSet):
    queryset = BlogPost.objects.filter(is_published=True)
    serializer_class = BlogPostSerializer
    
    # 3 Filter Backends configured simultaneously
    filter_backends = [
        DjangoFilterBackend,   # Exact & range filtering
        filters.SearchFilter,         # Full-text search (?search=...)
        filters.OrderingFilter       # Dynamic sorting (?ordering=-created_at)
    ]
    
    filterset_class = BlogPostFilter
    search_fields = ['title', 'summary', 'author__user__username']
    ordering_fields = ['created_at', 'premium_price', 'view_count']
    ordering = ['-created_at']  # Default sort

Clients can now perform powerful, compound queries effortlessly:

GET /api/posts/?category_slug=tech&min_price=10&search=django&ordering=-view_count&page=2

Building a Custom PageNumberPagination Class

Customize page sizes and client overrides by subclassing PageNumberPagination:

# blog/pagination.py
from rest_framework.pagination import PageNumberPagination

class CustomArticlePagination(PageNumberPagination):
    page_size = 12                      # Default items per page
    page_size_query_param = 'page_size' # Allows client: ?page_size=24
    max_page_size = 100                 # Hard cap to protect server memory
    page_query_param = 'p'              # Parameter: ?p=2

DRF Pagination Strategies Compared