[Django]-How to fix 'TypeError: __init__() got an unexpected keyword argument 'sender''

You are supposed to pass a Message model instance to MessageSerializer or a dict containing data with the keys specified in fields.

In case you want to pass a dict, pass the dict to data keyword.

message_dict = {'sender': request.user, 'chat_room': ChatRoom.objects.get(id=request.data['chat_room_id']), 'content': MessageContent(text=request.data['text'])}
message_serializer = MessageSerializer(data=message_dict)

if message_serializer.is_valid():
    message_serializer.save()

Make sure you have create method implemented in your MessageSerializer.