diff --git a/make/commands.py b/make/commands.py
index 3e34be355..a190688c3 100644
--- a/make/commands.py
+++ b/make/commands.py
@@ -12,7 +12,9 @@ def check(args=None):
     """
     Checks for pep8 and other code styling conventions.
     """
-    return call('flake8 --max-line-length=150 --statistics openslides tests')
+    value = call('flake8 --max-line-length=150 --statistics openslides tests')
+    value += call('python -m mypy openslides/ tests/')
+    return value
 
 
 @command('travis', help='Runs the code that travis does')
diff --git a/openslides/agenda/access_permissions.py b/openslides/agenda/access_permissions.py
index 8b602f935..dee6ffbcc 100644
--- a/openslides/agenda/access_permissions.py
+++ b/openslides/agenda/access_permissions.py
@@ -10,17 +10,8 @@ class ItemAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'agenda.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import ItemSerializer
-
-        return ItemSerializer
-
     # TODO: In the following method we use full_data['is_hidden'] and
     # full_data['is_internal'] but this can be out of date.
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
diff --git a/openslides/agenda/apps.py b/openslides/agenda/apps.py
index 3629d1407..5f2fe966d 100644
--- a/openslides/agenda/apps.py
+++ b/openslides/agenda/apps.py
@@ -22,6 +22,7 @@ class AgendaAppConfig(AppConfig):
             listen_to_related_object_post_delete,
             listen_to_related_object_post_save)
         from .views import ItemViewSet
+        from . import serializers  # noqa
         from ..utils.access_permissions import required_user
 
         # Define projector elements.
diff --git a/openslides/assignments/access_permissions.py b/openslides/assignments/access_permissions.py
index 05814a25e..7cadf883c 100644
--- a/openslides/assignments/access_permissions.py
+++ b/openslides/assignments/access_permissions.py
@@ -1,7 +1,7 @@
 from typing import Any, Dict, List
 
 from ..utils.access_permissions import BaseAccessPermissions
-from ..utils.auth import async_has_perm, has_perm
+from ..utils.auth import async_has_perm
 
 
 class AssignmentAccessPermissions(BaseAccessPermissions):
@@ -10,18 +10,6 @@ class AssignmentAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'assignments.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns different serializer classes according to users permissions.
-        """
-        from .serializers import AssignmentFullSerializer, AssignmentShortSerializer
-
-        if user is None or (has_perm(user, 'assignments.can_see') and has_perm(user, 'assignments.can_manage')):
-            serializer_class = AssignmentFullSerializer
-        else:
-            serializer_class = AssignmentShortSerializer
-        return serializer_class
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
diff --git a/openslides/assignments/apps.py b/openslides/assignments/apps.py
index 555faf16c..8db2e9138 100644
--- a/openslides/assignments/apps.py
+++ b/openslides/assignments/apps.py
@@ -15,11 +15,12 @@ class AssignmentsAppConfig(AppConfig):
     def ready(self):
         # Import all required stuff.
         from ..core.signals import permission_change
+        from ..utils.access_permissions import required_user
         from ..utils.rest_api import router
+        from . import serializers  # noqa
         from .projector import get_projector_elements
         from .signals import get_permission_change_data
         from .views import AssignmentViewSet, AssignmentPollViewSet
-        from ..utils.access_permissions import required_user
 
         # Define projector elements.
         register_projector_elements(get_projector_elements())
diff --git a/openslides/assignments/serializers.py b/openslides/assignments/serializers.py
index 438fd46f8..6b2cb1b2b 100644
--- a/openslides/assignments/serializers.py
+++ b/openslides/assignments/serializers.py
@@ -238,31 +238,3 @@ class AssignmentFullSerializer(ModelSerializer):
         assignment.agenda_item_update_information['parent_id'] = agenda_parent_id
         assignment.save()
         return assignment
-
-
-class AssignmentShortSerializer(AssignmentFullSerializer):
-    """
-    Serializer for assignment.models.Assignment objects. Without unpublished poll.
-    """
-    assignment_related_users = AssignmentRelatedUserSerializer(many=True, read_only=True)
-    polls = AssignmentShortPollSerializer(many=True, read_only=True)
-
-    class Meta:
-        model = Assignment
-        fields = (
-            'id',
-            'title',
-            'description',
-            'open_posts',
-            'phase',
-            'assignment_related_users',
-            'poll_description_default',
-            'polls',
-            'agenda_item_id',
-            'tags',)
-        validators = (posts_validator,)
-
-    def validate(self, data):
-        if 'description' in data:
-            data['description'] = validate_html(data['description'])
-        return data
diff --git a/openslides/core/access_permissions.py b/openslides/core/access_permissions.py
index 1a8ce04f5..b004f7199 100644
--- a/openslides/core/access_permissions.py
+++ b/openslides/core/access_permissions.py
@@ -8,28 +8,12 @@ class ProjectorAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'core.can_see_projector'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import ProjectorSerializer
-
-        return ProjectorSerializer
-
 
 class TagAccessPermissions(BaseAccessPermissions):
     """
     Access permissions container for Tag and TagViewSet.
     """
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import TagSerializer
-
-        return TagSerializer
-
 
 class ChatMessageAccessPermissions(BaseAccessPermissions):
     """
@@ -37,14 +21,6 @@ class ChatMessageAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'core.can_use_chat'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import ChatMessageSerializer
-
-        return ChatMessageSerializer
-
 
 class ProjectorMessageAccessPermissions(BaseAccessPermissions):
     """
@@ -52,14 +28,6 @@ class ProjectorMessageAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'core.can_see_projector'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import ProjectorMessageSerializer
-
-        return ProjectorMessageSerializer
-
 
 class CountdownAccessPermissions(BaseAccessPermissions):
     """
@@ -67,14 +35,6 @@ class CountdownAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'core.can_see_projector'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import CountdownSerializer
-
-        return CountdownSerializer
-
 
 class ConfigAccessPermissions(BaseAccessPermissions):
     """
@@ -82,14 +42,6 @@ class ConfigAccessPermissions(BaseAccessPermissions):
     ConfigViewSet).
     """
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import ConfigSerializer
-
-        return ConfigSerializer
-
 
 class HistoryAccessPermissions(BaseAccessPermissions):
     """
@@ -102,11 +54,3 @@ class HistoryAccessPermissions(BaseAccessPermissions):
         model instances.
         """
         return await async_in_some_groups(user_id, [GROUP_ADMIN_PK])
-
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import HistorySerializer
-
-        return HistorySerializer
diff --git a/openslides/core/apps.py b/openslides/core/apps.py
index 5fc3ac3e3..86958c32d 100644
--- a/openslides/core/apps.py
+++ b/openslides/core/apps.py
@@ -22,6 +22,7 @@ class CoreAppConfig(AppConfig):
         from ..utils.rest_api import router
         from ..utils.cache import element_cache
         from .projector import get_projector_elements
+        from . import serializers  # noqa
         from .signals import (
             delete_django_app_permissions,
             get_permission_change_data,
diff --git a/openslides/mediafiles/access_permissions.py b/openslides/mediafiles/access_permissions.py
index 2b438e1de..345bc6a72 100644
--- a/openslides/mediafiles/access_permissions.py
+++ b/openslides/mediafiles/access_permissions.py
@@ -10,14 +10,6 @@ class MediafileAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'mediafiles.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import MediafileSerializer
-
-        return MediafileSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
diff --git a/openslides/mediafiles/apps.py b/openslides/mediafiles/apps.py
index a7c340310..74c8dcfdc 100644
--- a/openslides/mediafiles/apps.py
+++ b/openslides/mediafiles/apps.py
@@ -18,6 +18,7 @@ class MediafilesAppConfig(AppConfig):
         from .projector import get_projector_elements
         from .signals import get_permission_change_data
         from .views import MediafileViewSet
+        from . import serializers  # noqa
         from ..utils.access_permissions import required_user
 
         # Define projector elements.
diff --git a/openslides/motions/access_permissions.py b/openslides/motions/access_permissions.py
index f3603778d..ce6f2cbb5 100644
--- a/openslides/motions/access_permissions.py
+++ b/openslides/motions/access_permissions.py
@@ -11,14 +11,6 @@ class MotionAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import MotionSerializer
-
-        return MotionSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
@@ -71,14 +63,6 @@ class MotionChangeRecommendationAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import MotionChangeRecommendationSerializer
-
-        return MotionChangeRecommendationSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
@@ -107,14 +91,6 @@ class MotionCommentSectionAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import MotionCommentSectionSerializer
-
-        return MotionCommentSectionSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
@@ -140,14 +116,6 @@ class StatuteParagraphAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import StatuteParagraphSerializer
-
-        return StatuteParagraphSerializer
-
 
 class CategoryAccessPermissions(BaseAccessPermissions):
     """
@@ -155,14 +123,6 @@ class CategoryAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import CategorySerializer
-
-        return CategorySerializer
-
 
 class MotionBlockAccessPermissions(BaseAccessPermissions):
     """
@@ -170,25 +130,9 @@ class MotionBlockAccessPermissions(BaseAccessPermissions):
     """
     base_permission = 'motions.can_see'
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import MotionBlockSerializer
-
-        return MotionBlockSerializer
-
 
 class WorkflowAccessPermissions(BaseAccessPermissions):
     """
     Access permissions container for Workflow and WorkflowViewSet.
     """
     base_permission = 'motions.can_see'
-
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import WorkflowSerializer
-
-        return WorkflowSerializer
diff --git a/openslides/motions/apps.py b/openslides/motions/apps.py
index 7ce32bdeb..553cd7411 100644
--- a/openslides/motions/apps.py
+++ b/openslides/motions/apps.py
@@ -21,6 +21,7 @@ class MotionsAppConfig(AppConfig):
             create_builtin_workflows,
             get_permission_change_data,
         )
+        from . import serializers  # noqa
         from .views import (
             CategoryViewSet,
             StatuteParagraphViewSet,
diff --git a/openslides/topics/access_permissions.py b/openslides/topics/access_permissions.py
index 49a254a73..b0a89a198 100644
--- a/openslides/topics/access_permissions.py
+++ b/openslides/topics/access_permissions.py
@@ -6,11 +6,3 @@ class TopicAccessPermissions(BaseAccessPermissions):
     Access permissions container for Topic and TopicViewSet.
     """
     base_permission = 'agenda.can_see'
-
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import TopicSerializer
-
-        return TopicSerializer
diff --git a/openslides/topics/apps.py b/openslides/topics/apps.py
index edc9f572e..5e89c4051 100644
--- a/openslides/topics/apps.py
+++ b/openslides/topics/apps.py
@@ -16,6 +16,7 @@ class TopicsAppConfig(AppConfig):
         from .projector import get_projector_elements
         from .signals import get_permission_change_data
         from .views import TopicViewSet
+        from . import serializers  # noqa
 
         # Define projector elements.
         register_projector_elements(get_projector_elements())
diff --git a/openslides/users/access_permissions.py b/openslides/users/access_permissions.py
index a8b6297e3..d85e065fd 100644
--- a/openslides/users/access_permissions.py
+++ b/openslides/users/access_permissions.py
@@ -10,14 +10,6 @@ class UserAccessPermissions(BaseAccessPermissions):
     Access permissions container for User and UserViewSet.
     """
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns different serializer classes with respect user's permissions.
-        """
-        from .serializers import UserFullSerializer
-
-        return UserFullSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
@@ -95,14 +87,6 @@ class GroupAccessPermissions(BaseAccessPermissions):
     Access permissions container for Groups. Everyone can see them
     """
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import GroupSerializer
-
-        return GroupSerializer
-
 
 class PersonalNoteAccessPermissions(BaseAccessPermissions):
     """
@@ -110,14 +94,6 @@ class PersonalNoteAccessPermissions(BaseAccessPermissions):
     can handle personal notes.
     """
 
-    def get_serializer_class(self, user=None):
-        """
-        Returns serializer class.
-        """
-        from .serializers import PersonalNoteSerializer
-
-        return PersonalNoteSerializer
-
     async def get_restricted_data(
             self,
             full_data: List[Dict[str, Any]],
diff --git a/openslides/utils/access_permissions.py b/openslides/utils/access_permissions.py
index 840315315..eb49737f5 100644
--- a/openslides/utils/access_permissions.py
+++ b/openslides/utils/access_permissions.py
@@ -1,8 +1,6 @@
 from typing import Any, Callable, Dict, List, Set
 
 from asgiref.sync import async_to_sync
-from django.db.models import Model
-from rest_framework.serializers import Serializer
 
 from .auth import async_anonymous_is_enabled, async_has_perm, user_to_user_id
 from .cache import element_cache
@@ -41,25 +39,6 @@ class BaseAccessPermissions:
         else:
             return bool(user_id) or await async_anonymous_is_enabled()
 
-    def get_serializer_class(self, user_id: int = 0) -> Serializer:
-        """
-        Returns different serializer classes according to users permissions.
-
-        This should return the serializer for full data access if user is
-        None. See get_full_data().
-        """
-        # TODO: Rewrite me by using an serializer_class attribute and removing
-        # the user_id argument.
-        raise NotImplementedError(
-            "You have to add the method 'get_serializer_class' to your "
-            "access permissions class.".format(self))
-
-    def get_full_data(self, instance: Model) -> Dict[str, Any]:
-        """
-        Returns all possible serialized data for the given instance.
-        """
-        return self.get_serializer_class()(instance).data
-
     async def get_restricted_data(
             self, full_data: List[Dict[str, Any]],
             user_id: int) -> List[Dict[str, Any]]:
@@ -71,11 +50,6 @@ class BaseAccessPermissions:
         the return is the same. Returns an empty list if the user has no read
         access. Returns reduced data if the user has limited access. Default:
         Returns full data if the user has read access to model instances.
-
-        Hint: You should override this method if your get_serializer_class()
-        method returns different serializers for different users or if you
-        have access restrictions in your view or viewset in methods like
-        retrieve() or list().
         """
         return full_data if await self.async_check_permissions(user_id) else []
 
diff --git a/openslides/utils/models.py b/openslides/utils/models.py
index d8f556e34..4b863e497 100644
--- a/openslides/utils/models.py
+++ b/openslides/utils/models.py
@@ -4,6 +4,7 @@ from django.core.exceptions import ImproperlyConfigured
 from django.db import models
 
 from .access_permissions import BaseAccessPermissions
+from .rest_api import model_serializer_classes
 from .utils import convert_camel_case_to_pseudo_snake_case
 
 
@@ -134,4 +135,5 @@ class RESTModelMixin:
         """
         Returns the full_data of the instance.
         """
-        return self.get_access_permissions().get_full_data(self)
+        serializer_class = model_serializer_classes[type(self)]
+        return serializer_class(self).data
diff --git a/openslides/utils/rest_api.py b/openslides/utils/rest_api.py
index ffb6e3b7f..7f2d368f4 100644
--- a/openslides/utils/rest_api.py
+++ b/openslides/utils/rest_api.py
@@ -2,6 +2,7 @@ from collections import OrderedDict
 from typing import Any, Dict, Iterable, Optional, Type
 
 from asgiref.sync import async_to_sync
+from django.db.models import Model
 from django.http import Http404
 from rest_framework import status
 from rest_framework.decorators import detail_route, list_route
@@ -32,6 +33,7 @@ from rest_framework.serializers import (
     PrimaryKeyRelatedField,
     RelatedField,
     Serializer,
+    SerializerMetaclass,
     SerializerMethodField,
     ValidationError,
 )
@@ -152,17 +154,44 @@ class PermissionMixin:
 
     def get_serializer_class(self) -> Type[Serializer]:
         """
-        Overridden method to return the serializer class given by the
-        access permissions container.
+        Overridden method to return the serializer class for the model.
         """
-        if self.get_access_permissions() is not None:
-            serializer_class = self.get_access_permissions().get_serializer_class(self.request.user)  # type: ignore
+        model = self.get_queryset().model  # type: ignore
+        try:
+            return model_serializer_classes[model]
+        except AttributeError:
+            # If there is no known serializer class for the model, return the
+            # default serializer class.
+            return super().get_serializer_class()  # type: ignore
+
+
+model_serializer_classes: Dict[Type[Model], Serializer] = {}
+
+
+class ModelSerializerRegisterer(SerializerMetaclass):
+    """
+    Meta class for model serializer that detects the corresponding model
+    and saves it.
+    """
+
+    def __new__(cls, name, bases, attrs):  # type: ignore
+        """
+        Detects the corresponding model from the ModelSerializer by
+        looking into the Meta-class.
+
+        Does nothing, if the Meta-class does not have the model attribute.
+        """
+        serializer_class = super().__new__(cls, name, bases, attrs)
+        try:
+            model = serializer_class.Meta.model
+        except AttributeError:
+            pass
         else:
-            serializer_class = super().get_serializer_class()  # type: ignore
+            model_serializer_classes[model] = serializer_class
         return serializer_class
 
 
-class ModelSerializer(_ModelSerializer):
+class ModelSerializer(_ModelSerializer, metaclass=ModelSerializerRegisterer):
     """
     ModelSerializer that changes the field names of related fields to
     FIELD_NAME_id.