diff --git a/api/v1/serializers/content.py b/api/v1/serializers/content.py
index e98faee2..6c352aa2 100644
--- a/api/v1/serializers/content.py
+++ b/api/v1/serializers/content.py
@@ -18,6 +18,18 @@ class ContentCreateSerializer(serializers.Serializer):
     type = serializers.ChoiceField(choices=TYPE_CHOICES)
     data = serializers.JSONField()
 
+    def to_representation(self, obj):
+        print(obj)
+        if isinstance(obj, Image):
+            return ImageSerializer(obj, context=self.context).to_representation(obj)
+        elif isinstance(obj, Text):
+            return TextSerializer(obj, context=self.context).to_representation(obj)
+        elif isinstance(obj, ImageText):
+            return ImageTextSerializer(obj, context=self.context).to_representation(obj)
+        elif isinstance(obj, Video):
+            return VideoSerializer(obj, context=self.context).to_representation(obj)
+        return super(ContentSerializer, self).to_representation(obj)
+
 
 class ImageObjectSerializer(serializers.ModelSerializer):
     image = Base64ImageField(
diff --git a/api/v1/serializers/course.py b/api/v1/serializers/course.py
index d348ce64..f0aadbee 100644
--- a/api/v1/serializers/course.py
+++ b/api/v1/serializers/course.py
@@ -7,6 +7,11 @@ from .content import (
     GallerySerializer, GalleryImageSerializer,
 )
 
+from apps.content.models import (
+    Content, Image, Text, ImageText, Video,
+    Gallery, GalleryImage, ImageObject,
+)
+
 
 class MaterialCreateSerializer(serializers.ModelSerializer):
 
@@ -29,7 +34,7 @@ class MaterialCreateSerializer(serializers.ModelSerializer):
 
 
 class MaterialSerializer(MaterialCreateSerializer):
-    cover = ImageObjectSerializer()
+    cover = ImageObjectSerializer(allow_null=True)
 
 
 class LikeSerializer(serializers.ModelSerializer):
@@ -130,14 +135,14 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                     i.position = c['data']['position']
                     i.title = c['data']['title']
                     i.course = course
-                    i.img = Image.objects.get(c['data']['img'])
+                    i.img = ImageObject.objects.get(id=c['data']['img']['id'])
                     i.save()
                 else:
                     i = Image.objects.create(
                         position=c['data']['position'],
                         title=c['data']['title'],
                         course=course,
-                        img=Image.objects.get(c['data']['img']),
+                        img=Image.objects.get(id=c['data']['img']['id']),
                     )
             elif c['type'] == 'image-text':
                 if 'id' in c['data']:
@@ -145,7 +150,7 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                     it.position = c['data']['position']
                     it.title = c['data']['title']
                     it.course = course
-                    it.img = Image.objects.get(c['data']['img'])
+                    it.img = ImageObject.objects.get(id=c['data']['img']['id'])
                     it.txt = c['data']['txt']
                     it.save()
                 else:
@@ -153,7 +158,7 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                         position=c['data']['position'],
                         title=c['data']['title'],
                         course=course,
-                        img=Image.objects.get(c['data']['img']),
+                        img=Image.objects.get(id=c['data']['img']['id']),
                         txt=c['data']['txt'],
                     )
             elif c['type'] == 'video':
@@ -187,8 +192,8 @@ class CourseCreateSerializer(serializers.ModelSerializer):
         return course
 
     def update(self, instance, validated_data):
-        materials = validated_data.pop('materials')
-        content = validated_data.pop('content')
+        materials = validated_data.pop('materials', [])
+        content = validated_data.pop('content', [])
 
         course = super().update(instance, validated_data)
 
@@ -214,14 +219,14 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                     i.position = c['data']['position']
                     i.title = c['data']['title']
                     i.course = course
-                    i.img = Image.objects.get(c['data']['img'])
+                    i.img = Image.objects.get(id=c['data']['img']['id'])
                     i.save()
                 else:
                     i = Image.objects.create(
                         position=c['data']['position'],
                         title=c['data']['title'],
                         course=course,
-                        img=Image.objects.get(c['data']['img']),
+                        img=Image.objects.get(id=c['data']['img']['id']),
                     )
             elif c['type'] == 'imagetext':
                 if 'id' in c['data']:
@@ -229,7 +234,7 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                     it.position = c['data']['position']
                     it.title = c['data']['title']
                     it.course = course
-                    it.img = Image.objects.get(c['data']['img'])
+                    it.img = Image.objects.get(id=c['data']['img']['id'])
                     it.txt = c['data']['txt']
                     it.save()
                 else:
@@ -237,7 +242,7 @@ class CourseCreateSerializer(serializers.ModelSerializer):
                         position=c['data']['position'],
                         title=c['data']['title'],
                         course=course,
-                        img=Image.objects.get(c['data']['img']),
+                        img=Image.objects.get(id=c['data']['img']['id']),
                         txt=c['data']['txt'],
                     )
             elif c['type'] == 'video':