diff --git a/api/serializers.py b/api/serializers.py
index b6459cf..c7c5a49 100644
--- a/api/serializers.py
+++ b/api/serializers.py
@@ -3,12 +3,16 @@ from tournaments.models.court import Court
 from tournaments.models import Club, LiveMatch, TeamScore, Tournament, CustomUser, Event, Round, GroupStage, Match, TeamRegistration, PlayerRegistration, Purchase, FailedApiCall, DateInterval, Log, DeviceToken, UnregisteredTeam, UnregisteredPlayer
 from django.contrib.auth import password_validation
 from django.utils.translation import gettext_lazy as _
+from django.db.utils import IntegrityError
+from django.conf import settings
+
 # email
 from django.template.loader import render_to_string
 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
 
 from shared.cryptography import encryption_util
@@ -48,6 +52,9 @@ class UserSerializer(serializers.ModelSerializer):
         if 'country' in validated_data:
             country = validated_data['country']
 
+        if CustomUser.objects.filter(username__iexact=validated_data['username'].lower()):
+            raise IntegrityError("Le nom d'utilisateur existe déjà")
+
         user = CustomUser.objects.create_user(
             username=validated_data['username'],
             email=validated_data['email'],
@@ -73,7 +80,8 @@ class UserSerializer(serializers.ModelSerializer):
             origin=UserOrigin.APP,
         )
 
-        self.send_email(self.context['request'], user)
+        if not settings.DEBUG:
+            self.send_email(self.context['request'], user)
         # RegistrationProfile.objects.filter(user=user).send_activation_email()
 
         return user
diff --git a/api/views.py b/api/views.py
index 0f12567..b2f2d8f 100644
--- a/api/views.py
+++ b/api/views.py
@@ -59,7 +59,7 @@ class CustomAuthToken(APIView):
             user = CustomUser.objects.get(email=email)
             return user.username
         except ObjectDoesNotExist:
-            return None  # or handle the case where the user doesn't exist
+            return None
 
 class Logout(APIView):
     permission_classes = (IsAuthenticated,)
diff --git a/tournaments/forms.py b/tournaments/forms.py
index aef159a..82373bc 100644
--- a/tournaments/forms.py
+++ b/tournaments/forms.py
@@ -58,6 +58,14 @@ class SimpleCustomUserCreationForm(UserCreationForm):
             'password2': 'Confirmer le mot de passe',
         }
 
+    def clean_username(self):
+        username = self.cleaned_data.get('username')
+        if username:
+            username = username.lower()
+            if CustomUser.objects.filter(username__iexact=username).exists():
+                raise forms.ValidationError("Le nom d'utilisateur existe déjà")
+        return username
+
 
 class CustomUserChangeForm(UserChangeForm):
 
diff --git a/tournaments/signals.py b/tournaments/signals.py
index 735f1ec..ea47ab2 100644
--- a/tournaments/signals.py
+++ b/tournaments/signals.py
@@ -6,6 +6,7 @@ from django.conf import settings
 from tournaments.models.tournament import Tournament
 from tournaments.models.unregistered_player import UnregisteredPlayer
 from django.utils import timezone
+from django.db.utils import IntegrityError
 
 from .models import Club, FailedApiCall, CustomUser, Log, TeamRegistration, PlayerRegistration, UnregisteredTeam, UnregisteredPlayer, TeamSortingType
 import requests
@@ -15,6 +16,12 @@ from tournaments.models import PlayerDataSource
 from shared.discord import send_discord_log_message, send_discord_failed_calls_message
 from datetime import datetime
 
+# @receiver(pre_save, sender=CustomUser)
+# def username_check(instance, sender, **kwargs):
+#     """Ensure that username unique constraint is case insensitive"""
+#     if sender.objects.filter(username__iexact=instance.username.lower()):
+#         raise IntegrityError("Le nom d'utilisateur existe déjà")
+
 def generate_unique_code():
     characters = string.ascii_lowercase + string.digits
     while True:
diff --git a/tournaments/views.py b/tournaments/views.py
index 33fbc32..5eefc8c 100644
--- a/tournaments/views.py
+++ b/tournaments/views.py
@@ -1,17 +1,21 @@
 # Standard library imports
 import os
 import csv
+
 from django.shortcuts import render, get_object_or_404
-from django.http import HttpResponse
+from django.http import JsonResponse, HttpResponse
 from django.utils.encoding import force_str
 from django.utils.http import urlsafe_base64_encode, urlsafe_base64_decode
 from django.urls import reverse
+from django.conf import settings
 
 from django.views.decorators.csrf import csrf_exempt
 from django.contrib.admin.views.decorators import staff_member_required
 from django.core.files.storage import default_storage
 from django.core.files.base import ContentFile
 from django.views.generic import View
+from django.db.models import Q
+from django.template import loader
 
 from tournaments.models.device_token import DeviceToken
 
@@ -20,10 +24,7 @@ from .models import TeamSummon
 from datetime import datetime, timedelta
 import time
 
-from django.template import loader
 from datetime import date
-from django.http import JsonResponse, HttpResponse
-from django.db.models import Q
 import json
 import time
 import asyncio
@@ -638,7 +639,8 @@ def signup(request):
             user.origin = UserOrigin.SITE
             user.save()
 
-            send_verification_email(request, user, next_url)
+            if not settings.DEBUG:
+                send_verification_email(request, user, next_url)
 
             return render(request, 'registration/signup_success.html', {
                 'next_url': next_url,