diff --git a/README.md b/README.md
index 2a73b0f..d20dca3 100644
--- a/README.md
+++ b/README.md
@@ -15,5 +15,36 @@ MIDDLEWARE = [
 ]
 ```
 
+
+Define a Response function and pass it in settings.py to `JSON404_DATA_RESPONSE`
+
+
+```python
+# in settings.py
+# import mycustoomfunction
+JSON_DATA_RESPONSE = mycustomfunction
+```
+
+
+Example of custom response function
+
+
+```python
+from django.http import JsonResponse
+
+
+def json404_response(request):
+
+    data = {
+        "detail": "not found",
+        "title": "Not found.",
+        "status": 404,
+        "type": "{}://{}/problems/not_found/",
+    }
+    data["type"] = data["type"].format(request.scheme, request.get_host())
+    return JsonResponse(data, content_type="application/problem+json", status=404)
+```
+
+
 # Installation
-`pip install django-json-404-middleware`
\ No newline at end of file
+`pip install django-json-404-middleware`
diff --git a/django_json_404_middleware/middleware.py b/django_json_404_middleware/middleware.py
index 09974a6..5b46bc5 100644
--- a/django_json_404_middleware/middleware.py
+++ b/django_json_404_middleware/middleware.py
@@ -1,16 +1,30 @@
-from django.http import HttpResponse
-import json
+from django.conf import settings
+from django.http import JsonResponse
+
+
+def default_response(request):
+    data = {"detail": "{0} not found".format(request.path)}
+    return JsonResponse(data, content_type="application/json", status=404)
+
 
 class JSON404Middleware(object):
-	"""
-	Returns JSON 404 instead of HTML
-	"""
-	def __init__(self, get_response):
-		self.get_response = get_response
+    """
+    Returns JSON 404 instead of HTML
+    """
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+        try:
+            self.data_function = settings.JSON404_DATA_FUNCTION
+        except AttributeError:
+            self.data_function = default_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+        if (
+            response.status_code == 404
+            and "text/html" in response["content-type"]
+        ):
+            response = self.data_function(request)
 
-	def __call__(self, request):
-		response = self.get_response(request)
-		if response.status_code == 404 and 'application/json' not in response['content-type']:
-			data = {'detail': '{0} not found'.format(request.path)}
-			response = HttpResponse(json.dumps(data), content_type='application/json', status=404)
-		return response
\ No newline at end of file
+        return response