diff --git a/invites/models.py b/invites/models.py
index ef2888d2..36f4c72e 100644
--- a/invites/models.py
+++ b/invites/models.py
@@ -38,7 +38,7 @@ class Invite(models.Model):
     objects = InviteManager()
 
     def __str__(self):
-        return f'Invite from "{self.project.name}" to {self.user.get_full_name()}'
+        return f'Invite from project "{self.project.name}" to {self.user.get_full_name()}'
 
     class Meta:
         verbose_name = "Приглашение"
diff --git a/invites/serializers.py b/invites/serializers.py
index 9a91fdb1..afea5064 100644
--- a/invites/serializers.py
+++ b/invites/serializers.py
@@ -1,10 +1,14 @@
 from rest_framework import serializers
 
 from invites.models import Invite
+from projects.serializers import ProjectListSerializer
 from users.serializers import UserDetailSerializer
 
 
 class InviteListSerializer(serializers.ModelSerializer):
+    user = UserDetailSerializer(many=False, read_only=True)
+    project = ProjectListSerializer(many=False, read_only=True)
+
     class Meta:
         model = Invite
         fields = [
diff --git a/projects/views.py b/projects/views.py
index bc858405..387b805b 100644
--- a/projects/views.py
+++ b/projects/views.py
@@ -14,7 +14,6 @@
     ProjectListSerializer,
     AchievementDetailSerializer,
     ProjectCollaboratorSerializer,
-    ProjectAchievementListSerializer,
 )
 
 
@@ -77,23 +76,19 @@ def put(self, request, pk, **kwargs):
         # bootleg version of updating achievements via project
         if request.data.get("achievements") is not None:
             achievements = request.data.get("achievements")
-            for achievement in achievements:
-                achievement_id = achievement.get("id")
-                if achievement_id is None:
-                    # creating
-                    achievement["project"] = pk
-                    serializer = ProjectAchievementListSerializer(data=achievement)
-                    serializer.is_valid(raise_exception=True)
-                    serializer.save()
-                else:
-                    # changing
-                    instance = Achievement.objects.get(id=achievement_id)
-                    achievement["project"] = pk
-                    serializer = AchievementDetailSerializer(
-                        instance, data=achievement, partial=False
+            # delete all old achievements
+            Achievement.objects.filter(project_id=pk).delete()
+            # create new achievements
+            Achievement.objects.bulk_create(
+                [
+                    Achievement(
+                        project_id=pk,
+                        title=achievement.get("name"),
+                        status=achievement.get("description"),
                     )
-                    serializer.is_valid(raise_exception=True)
-                    serializer.save()
+                    for achievement in achievements
+                ]
+            )
 
         return super(ProjectDetail, self).put(request, pk)
 
diff --git a/users/views.py b/users/views.py
index 8ddce830..ee5b76ac 100644
--- a/users/views.py
+++ b/users/views.py
@@ -111,22 +111,19 @@ def put(self, request, pk):
         # bootleg version of updating achievements via user
         if request.data.get("achievements") is not None:
             achievements = request.data.get("achievements")
-            for achievement in achievements:
-                achievement_id = achievement.get("id")
-                if achievement_id is None:
-                    UserAchievement.objects.create(
-                        title=achievement["title"],
-                        status=achievement["status"],
+            # delete all old achievements
+            UserAchievement.objects.filter(user_id=pk).delete()
+            # create new achievements
+            UserAchievement.objects.bulk_create(
+                [
+                    UserAchievement(
                         user_id=pk,
+                        title=achievement.get("name"),
+                        status=achievement.get("description"),
                     )
-                    continue
-                instance = UserAchievement.objects.get(id=achievement_id)
-                achievement["user"] = pk
-                serializer = AchievementDetailSerializer(
-                    instance, data=achievement, partial=False
-                )
-                serializer.is_valid(raise_exception=True)
-                serializer.save()
+                    for achievement in achievements
+                ]
+            )
         return super().put(request, pk)