Introduction: Why Rate Limiting Matters

APIs are like highways—without traffic control, they can get clogged or even crash. One common source of "traffic jams" in APIs is anonymous users making too many requests. This could be bots, scrapers, or just poorly configured clients. That's where Django REST Framework’s AnonRateThrottle comes in.

AnonRateThrottle helps you prevent abuse by limiting the number of requests non-authenticated users can make in a given timeframe. It’s an essential tool for protecting your API from anonymous flood attacks and preserving server resources.

What is AnonRateThrottle?

AnonRateThrottle is a built-in throttle class in Django REST Framework (DRF). It tracks request rates per IP address for unauthenticated users and ensures they don’t exceed a pre-defined limit.

It works by:

• Identifying unauthenticated users

• Counting how many requests they make in a timeframe (like per minute/hour/day)

• Temporarily blocking further requests if they exceed the threshold

Step-by-Step: How to Use AnonRateThrottle

1. Enable Throttling in Django Settings

Add or modify the following settings in your settings.py:

REST_FRAMEWORK = {
    'DEFAULT_THROTTLE_CLASSES': [
        'rest_framework.throttling.AnonRateThrottle',
    ],
    'DEFAULT_THROTTLE_RATES': {
        'anon': '10/minute',  # Limit anonymous users to 10 requests per minute
    }
}

Throttle format: 'scope': 'number/period', where period = second | minute | hour | day

2. Apply to Views or ViewSets (Optional)

You can enforce throttling globally (as above) or apply it selectively using throttle_classes.

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.throttling import AnonRateThrottle

class PublicAPI(APIView):
    throttle_classes = [AnonRateThrottle]

    def get(self, request):
        return Response({"message": "This endpoint is protected by AnonRateThrottle."})

3. Customize Response for Throttled Requests (Optional)

Override throttled() method to provide custom error responses:

from rest_framework.exceptions import Throttled

class CustomThrottle(AnonRateThrottle):
    def throttled(self, request, wait):
        raise Throttled(detail={
            "error": "Rate limit exceeded. Try again in {} seconds.".format(wait)
        })

Full Working Example

Here’s a minimal Django REST project with AnonRateThrottle configured.

settings.py

REST_FRAMEWORK = {
    'DEFAULT_THROTTLE_CLASSES': [
        'rest_framework.throttling.AnonRateThrottle',
    ],
    'DEFAULT_THROTTLE_RATES': {
        'anon': '5/minute',
    }
}

views.py

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.throttling import AnonRateThrottle

class PublicEndpoint(APIView):
    throttle_classes = [AnonRateThrottle]

    def get(self, request):
        return Response({"message": "This is a throttled public endpoint."})

urls.py

from django.urls import path
from .views import PublicEndpoint

urlpatterns = [
    path('public/', PublicEndpoint.as_view(), name='public-endpoint'),
]

Test it using a browser or tool like curl:

curl http://localhost:8000/public/

After 5 rapid requests, you’ll start getting HTTP 429 Too Many Requests.

⚠️ Tips & Common Pitfalls

✅ Best Practices

• Set realistic rate limits: Too strict = frustrates users; too lenient = invites abuse.

• Combine with AuthRateThrottle for authenticated users.

• Monitor throttle logs to tune settings over time.

❌ Common Mistakes

Comparison Table: AnonRateThrottle vs AuthRateThrottle

Conclusion: Protect Smartly, Not Harshly

AnonRateThrottle is a simple yet powerful safeguard for Django APIs. It allows you to:

• Prevent anonymous abuse

• Conserve backend resources

• Improve overall system stability

✅ Best practice: Start with a moderate limit (e.g., 10/minute), monitor traffic, and adjust accordingly.