diff --git a/api/serializers.py b/api/serializers.py
index ec03749..61ac1a0 100644
--- a/api/serializers.py
+++ b/api/serializers.py
@@ -9,7 +9,6 @@ from django.utils.http import urlsafe_base64_encode, urlsafe_base64_decode
 from django.utils.encoding import force_bytes
 from django.core.mail import EmailMessage
 from django.contrib.sites.shortcuts import get_current_site
-
 from api.tokens import account_activation_token
 
 class UserSerializer(serializers.ModelSerializer):
diff --git a/api/views.py b/api/views.py
index b8d93d2..18c21ce 100644
--- a/api/views.py
+++ b/api/views.py
@@ -107,6 +107,38 @@ class PurchaseViewSet(viewsets.ModelViewSet):
             return self.queryset.filter(user=self.request.user)
         return []
 
+    def create(self, request, *args, **kwargs):
+        identifier = request.data.get('identifier')
+        if Purchase.objects.filter(identifier=identifier).exists():
+            return Response({"detail": "This transaction identifier is already registered."}, status=status.HTTP_208_ALREADY_REPORTED)
+
+        serializer = self.get_serializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+        self.perform_create(serializer)
+        headers = self.get_success_headers(serializer.data)
+        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
+
+    # def create(self, request, *args, **kwargs):
+    #     serializer = PurchaseSerializer(data=request.data)
+    #     # Check if the serializer is valid
+    #     #
+    #     print('create')
+    #     if serializer.is_valid():
+    #         print('isvalid')
+
+    #         identifier = serializer.validated_data['identifier']
+    #         # If the unique field already exists, return 208
+    #         if Purchase.objects.filter(identifier=identifier).exists():
+    #             print('return 208')
+
+    #             return Response({'detail': 'Already exists.'}, status=status.HTTP_208_ALREADY_REPORTED)
+    #         # Otherwise, perform the creation
+    #         self.perform_create(serializer)
+    #         return Response(serializer.data, status=status.HTTP_201_CREATED)
+    #     print('return 400')
+
+    #     return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
     def put(self, request, pk):
         raise MethodNotAllowed('PUT')
 
diff --git a/tournaments/migrations/0082_alter_purchase_identifier_and_more.py b/tournaments/migrations/0082_alter_purchase_identifier_and_more.py
new file mode 100644
index 0000000..0310ea3
--- /dev/null
+++ b/tournaments/migrations/0082_alter_purchase_identifier_and_more.py
@@ -0,0 +1,23 @@
+# Generated by Django 5.1 on 2024-09-16 08:20
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tournaments', '0081_round_group_stage_loser_bracket'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='purchase',
+            name='identifier',
+            field=models.BigIntegerField(unique=True),
+        ),
+        migrations.AlterField(
+            model_name='tournament',
+            name='federal_age_category',
+            field=models.IntegerField(choices=[(0, ''), (120, 'U12'), (140, 'U14'), (160, 'U16'), (180, 'U18'), (200, 'Senior'), (450, '+45 ans'), (550, '+55 ans')], default=200),
+        ),
+    ]
diff --git a/tournaments/models/purchase.py b/tournaments/models/purchase.py
index 6dc72e4..da2b335 100644
--- a/tournaments/models/purchase.py
+++ b/tournaments/models/purchase.py
@@ -5,7 +5,7 @@ from . import CustomUser
 class Purchase(models.Model):
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=True)
     user = models.ForeignKey(CustomUser, on_delete=models.CASCADE)
-    identifier = models.BigIntegerField()
+    identifier = models.BigIntegerField(unique=True)
     purchase_date = models.DateTimeField()
     product_id = models.CharField(max_length=100)
     quantity = models.IntegerField(null=True, blank=True)