diff --git a/backend/api/tests/api/test_annotation.py b/backend/api/tests/api/test_annotation.py
index 242f88c5..ac924faf 100644
--- a/backend/api/tests/api/test_annotation.py
+++ b/backend/api/tests/api/test_annotation.py
@@ -7,15 +7,17 @@ from .utils import (CRUDMixin, make_annotation, make_doc, make_label,
 
 
 class TestAnnotationList(CRUDMixin):
+    task = DOCUMENT_CLASSIFICATION
+    view_name = 'annotation_list'
 
     @classmethod
     def setUpTestData(cls):
-        cls.project = prepare_project(task=DOCUMENT_CLASSIFICATION)
+        cls.project = prepare_project(task=cls.task)
         cls.non_member = make_user()
         doc = make_doc(cls.project.item)
         for member in cls.project.users:
-            make_annotation(task=DOCUMENT_CLASSIFICATION, doc=doc, user=member)
-        cls.url = reverse(viewname='annotation_list', args=[cls.project.item.id, doc.id])
+            make_annotation(task=cls.task, doc=doc, user=member)
+        cls.url = reverse(viewname=cls.view_name, args=[cls.project.item.id, doc.id])
 
     def test_allows_project_member_to_fetch_annotation(self):
         for member in self.project.users:
@@ -34,15 +36,21 @@ class TestAnnotationList(CRUDMixin):
         self.assertEqual(count, 2)  # delete only own annotation
 
 
+class TestCategoryList(TestAnnotationList):
+    view_name = 'category_list'
+
+
 class TestSharedAnnotationList(CRUDMixin):
+    task = DOCUMENT_CLASSIFICATION
+    view_name = 'annotation_list'
 
     @classmethod
     def setUpTestData(cls):
-        cls.project = prepare_project(task=DOCUMENT_CLASSIFICATION, collaborative_annotation=True)
+        cls.project = prepare_project(task=cls.task, collaborative_annotation=True)
         doc = make_doc(cls.project.item)
         for member in cls.project.users:
-            make_annotation(task=DOCUMENT_CLASSIFICATION, doc=doc, user=member)
-        cls.url = reverse(viewname='annotation_list', args=[cls.project.item.id, doc.id])
+            make_annotation(task=cls.task, doc=doc, user=member)
+        cls.url = reverse(viewname=cls.view_name, args=[cls.project.item.id, doc.id])
 
     def test_allows_project_member_to_fetch_all_annotation(self):
         for member in self.project.users:
@@ -55,15 +63,21 @@ class TestSharedAnnotationList(CRUDMixin):
         self.assertEqual(count, 0)  # delete all annotation in the doc
 
 
+class TestSharedCategoryList(TestSharedAnnotationList):
+    view_name = 'category_list'
+
+
 class TestAnnotationCreation(CRUDMixin):
+    task = DOCUMENT_CLASSIFICATION
+    view_name = 'annotation_list'
 
     def setUp(self):
-        self.project = prepare_project(task=DOCUMENT_CLASSIFICATION)
+        self.project = prepare_project(task=self.task)
         self.non_member = make_user()
         doc = make_doc(self.project.item)
         label = make_label(self.project.item)
         self.data = {'label': label.id}
-        self.url = reverse(viewname='annotation_list', args=[self.project.item.id, doc.id])
+        self.url = reverse(viewname=self.view_name, args=[self.project.item.id, doc.id])
 
     def test_allows_project_member_to_annotate(self):
         for member in self.project.users:
@@ -76,22 +90,31 @@ class TestAnnotationCreation(CRUDMixin):
         self.assert_create(expected=status.HTTP_403_FORBIDDEN)
 
 
+class TestCategoryCreation(TestAnnotationCreation):
+    view_name = 'category_list'
+
+
 class TestAnnotationDetail(CRUDMixin):
+    task = SEQUENCE_LABELING
+    view_name = 'annotation_detail'
 
     def setUp(self):
-        self.project = prepare_project(task=SEQUENCE_LABELING)
+        self.project = prepare_project(task=self.task)
         self.non_member = make_user()
         doc = make_doc(self.project.item)
         label = make_label(self.project.item)
-        annotation = make_annotation(
-            task=SEQUENCE_LABELING,
+        annotation = self.create_annotation_data(doc=doc)
+        self.data = {'label': label.id}
+        self.url = reverse(viewname=self.view_name, args=[self.project.item.id, doc.id, annotation.id])
+
+    def create_annotation_data(self, doc):
+        return make_annotation(
+            task=self.task,
             doc=doc,
             user=self.project.users[0],
             start_offset=0,
             end_offset=1
         )
-        self.data = {'label': label.id}
-        self.url = reverse(viewname='annotation_detail', args=[self.project.item.id, doc.id, annotation.id])
 
     def test_allows_owner_to_get_annotation(self):
         self.assert_fetch(self.project.users[0], status.HTTP_200_OK)
@@ -127,15 +150,25 @@ class TestAnnotationDetail(CRUDMixin):
         self.assert_delete(self.non_member, status.HTTP_403_FORBIDDEN)
 
 
+class TestCategoryDetail(TestAnnotationDetail):
+    task = DOCUMENT_CLASSIFICATION
+    view_name = 'category_detail'
+
+    def create_annotation_data(self, doc):
+        return make_annotation(task=self.task, doc=doc, user=self.project.users[0])
+
+
 class TestSharedAnnotationDetail(CRUDMixin):
+    task = DOCUMENT_CLASSIFICATION
+    view_name = 'annotation_detail'
 
     def setUp(self):
-        self.project = prepare_project(task=DOCUMENT_CLASSIFICATION, collaborative_annotation=True)
+        self.project = prepare_project(task=self.task, collaborative_annotation=True)
         doc = make_doc(self.project.item)
-        annotation = make_annotation(task=DOCUMENT_CLASSIFICATION, doc=doc, user=self.project.users[0])
+        annotation = make_annotation(task=self.task, doc=doc, user=self.project.users[0])
         label = make_label(self.project.item)
         self.data = {'label': label.id}
-        self.url = reverse(viewname='annotation_detail', args=[self.project.item.id, doc.id, annotation.id])
+        self.url = reverse(viewname=self.view_name, args=[self.project.item.id, doc.id, annotation.id])
 
     def test_allows_any_member_to_get_annotation(self):
         for member in self.project.users:
@@ -147,3 +180,7 @@ class TestSharedAnnotationDetail(CRUDMixin):
 
     def test_allows_any_member_to_delete_annotation(self):
         self.assert_delete(self.project.users[1], status.HTTP_204_NO_CONTENT)
+
+
+class TestSharedCategoryDetail(TestSharedAnnotationDetail):
+    view_name = 'category_detail'
diff --git a/backend/api/urls.py b/backend/api/urls.py
index 6493e657..32497403 100644
--- a/backend/api/urls.py
+++ b/backend/api/urls.py
@@ -4,6 +4,7 @@ from .views import (annotation, annotation_relations, auto_labeling, comment,
                     example, example_state, export_dataset, health,
                     import_dataset, import_export, label, project,
                     relation_types, role, statistics, tag, task, user)
+from .views.tasks import category
 
 urlpatterns_project = [
     path(
@@ -112,6 +113,16 @@ urlpatterns_project = [
         view=annotation.AnnotationDetail.as_view(),
         name='annotation_detail'
     ),
+    path(
+        route='examples/<int:example_id>/categories',
+        view=category.CategoryListAPI.as_view(),
+        name='category_list'
+    ),
+    path(
+        route='examples/<int:example_id>/categories/<int:annotation_id>',
+        view=category.CategoryDetailAPI.as_view(),
+        name='category_detail'
+    ),
     path(
         route='tags',
         view=tag.TagList.as_view(),
diff --git a/backend/api/views/tasks/__init__.py b/backend/api/views/tasks/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/backend/api/views/tasks/base.py b/backend/api/views/tasks/base.py
new file mode 100644
index 00000000..ebcf22ff
--- /dev/null
+++ b/backend/api/views/tasks/base.py
@@ -0,0 +1,57 @@
+from django.core.exceptions import ValidationError
+from django.shortcuts import get_object_or_404
+from rest_framework import generics, status
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+
+from ...models import Project
+from ...permissions import IsInProjectOrAdmin, IsOwnAnnotation
+
+
+class BaseListAPI(generics.ListCreateAPIView):
+    annotation_class = None
+    pagination_class = None
+    permission_classes = [IsAuthenticated & IsInProjectOrAdmin]
+    swagger_schema = None
+
+    @property
+    def project(self):
+        return get_object_or_404(Project, pk=self.kwargs['project_id'])
+
+    def get_queryset(self):
+        queryset = self.annotation_class.objects.filter(example=self.kwargs['example_id'])
+        if not self.project.collaborative_annotation:
+            queryset = queryset.filter(user=self.request.user)
+        return queryset
+
+    def create(self, request, *args, **kwargs):
+        request.data['example'] = self.kwargs['example_id']
+        try:
+            response = super().create(request, args, kwargs)
+        except ValidationError as err:
+            response = Response({'detail': err.messages}, status=status.HTTP_400_BAD_REQUEST)
+        return response
+
+    def perform_create(self, serializer):
+        serializer.save(example_id=self.kwargs['example_id'], user=self.request.user)
+
+    def delete(self, request, *args, **kwargs):
+        queryset = self.get_queryset()
+        queryset.all().delete()
+        return Response(status=status.HTTP_204_NO_CONTENT)
+
+
+class BaseDetailAPI(generics.RetrieveUpdateDestroyAPIView):
+    lookup_url_kwarg = 'annotation_id'
+    swagger_schema = None
+
+    @property
+    def project(self):
+        return get_object_or_404(Project, pk=self.kwargs['project_id'])
+
+    def get_permissions(self):
+        if self.project.collaborative_annotation:
+            self.permission_classes = [IsAuthenticated & IsInProjectOrAdmin]
+        else:
+            self.permission_classes = [IsAuthenticated & IsInProjectOrAdmin & IsOwnAnnotation]
+        return super().get_permissions()
diff --git a/backend/api/views/tasks/category.py b/backend/api/views/tasks/category.py
new file mode 100644
index 00000000..7f3eee5d
--- /dev/null
+++ b/backend/api/views/tasks/category.py
@@ -0,0 +1,18 @@
+from ...models import Category
+from ...serializers import CategorySerializer
+from .base import BaseDetailAPI, BaseListAPI
+
+
+class CategoryListAPI(BaseListAPI):
+    annotation_class = Category
+    serializer_class = CategorySerializer
+
+    def create(self, request, *args, **kwargs):
+        if self.project.single_class_classification:
+            self.get_queryset().delete()
+        return super().create(request, args, kwargs)
+
+
+class CategoryDetailAPI(BaseDetailAPI):
+    queryset = Category.objects.all()
+    serializer_class = CategorySerializer