diff --git a/apps/account/serializers/common.py b/apps/account/serializers/common.py
index deb0217e..b6de5bb0 100644
--- a/apps/account/serializers/common.py
+++ b/apps/account/serializers/common.py
@@ -4,9 +4,11 @@ from django.contrib.auth import password_validation as password_validators
 from fcm_django.models import FCMDevice
 from rest_framework import exceptions
 from rest_framework import serializers
+from rest_framework import validators as rest_validators
 
 from account import models, tasks
 from utils import exceptions as utils_exceptions
+from utils import methods as utils_methods
 
 
 # User serializers
@@ -17,12 +19,17 @@ class UserSerializer(serializers.ModelSerializer):
     fullname = serializers.CharField(source='get_full_name', read_only=True)
 
     # REQUEST
-    username = serializers.CharField(required=False)
+    username = serializers.CharField(
+        validators=(rest_validators.UniqueValidator(queryset=models.User.objects.all()),),
+        write_only=True,
+        required=False)
     first_name = serializers.CharField(required=False, write_only=True)
     last_name = serializers.CharField(required=False, write_only=True)
     image = serializers.ImageField(required=False)
     cropped_image = serializers.ImageField(required=False)
-    email = serializers.EmailField(required=False)
+    email = serializers.EmailField(
+        validators=(rest_validators.UniqueValidator(queryset=models.User.objects.all()),),
+        required=False)
     newsletter = serializers.BooleanField(required=False)
 
     class Meta:
@@ -43,14 +50,13 @@ class UserSerializer(serializers.ModelSerializer):
         """Validate email value"""
         if value == self.instance.email:
             raise serializers.ValidationError()
-        if models.User.objects.filter(email=value).exists():
-            raise serializers.ValidationError()
         return value
 
     def validate_username(self, value):
-        """Validate username"""
-        if models.User.objects.filter(username=value).exists():
-            raise serializers.ValidationError()
+        """Custom username validation"""
+        valid = utils_methods.username_validator(username=value)
+        if not valid:
+            raise utils_exceptions.NotValidUsernameError()
         return value
 
     def validate(self, attrs):
diff --git a/apps/authorization/serializers/common.py b/apps/authorization/serializers/common.py
index e5c615e0..5817e191 100644
--- a/apps/authorization/serializers/common.py
+++ b/apps/authorization/serializers/common.py
@@ -21,8 +21,7 @@ class SignupSerializer(serializers.ModelSerializer):
     # REQUEST
     username = serializers.CharField(
         validators=(rest_validators.UniqueValidator(queryset=account_models.User.objects.all()),),
-        write_only=True
-    )
+        write_only=True)
     password = serializers.CharField(write_only=True)
     email = serializers.EmailField(
         validators=(rest_validators.UniqueValidator(queryset=account_models.User.objects.all()),),
@@ -38,21 +37,21 @@ class SignupSerializer(serializers.ModelSerializer):
             'newsletter'
         )
 
-    def validate_username(self, data):
+    def validate_username(self, value):
         """Custom username validation"""
-        valid = utils_methods.username_validator(username=data)
+        valid = utils_methods.username_validator(username=value)
         if not valid:
             raise utils_exceptions.NotValidUsernameError()
-        return data
+        return value
 
-    def validate_password(self, data):
+    def validate_password(self, value):
         """Custom password validation"""
         try:
-            password_validators.validate_password(password=data)
+            password_validators.validate_password(password=value)
         except serializers.ValidationError as e:
             raise serializers.ValidationError(str(e))
         else:
-            return data
+            return value
 
     def create(self, validated_data):
         """Override create method"""