Adding information to JWT token body using django rest framework jwt

Using the djangorestframework_simplejwt library

1. Specify in settings.py the USER_ID_FIELD and ALGORITHM

   SIMPLE_JWT = {
       'USER_ID_FIELD': 'user_id',
       'ALGORITHM': 'HS512',
   }
   

Let's say you want to add fields to the body of TokenObtainPairView which has the following body

{
    "refresh": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ0b2tlbl90eXBlIjoicmVmcmVzaCIsImV4cCI6MTU5MDk5ODAwMSwianRpIjoiMjZhZThhYTU4YTJiNDU3M2JlMDgxNTMzMzU1ODg4ZmUiLCJ1c2VyX2lkIjoxMX0.-jUCnfpTF-RsqHnuoEgctPpHf1SfYNcYaPs8oo01RvrQBMcyhms5PfWipfYkaR0FlPHSTKncNeMxomwd4k7nyg",
    "access": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiZXhwIjoxNTkwOTExOTAxLCJqdGkiOiI5NjZkOTFhNzEzNjg0NjMyOGUzYWU3NThiNzNiZmYxMyIsInVzZXJfaWQiOjExfQ.LiHrekmlHrM7_5187ghpIaA6mKcPCjDz4MDKPXHc4QAKVGvcJCJpCjrODCB4-pZn4Kuai5ht3YjWwYSirxpsXw"
}

2. Add in your urls.py

   path('api/token/', MyTokenObtainPairView.as_view(), name='token_obtain'),
   

3. Create the MyTokenObtainPairView

   class MyTokenObtainPairView(TokenObtainPairView):
       serializer_class = MyTokenObtainPairSerializer`
   

4. Create the MyTokenObtainPairSerializer

   class MyTokenObtainPairSerializer(TokenObtainPairSerializer):
       def validate(self, attrs):
           data = super().validate(attrs)
           refresh = self.get_token(self.user)
           data['refresh'] = str(refresh)
           data.pop('refresh', None) # remove refresh from the payload
           data['access'] = str(refresh.access_token)
   
           # Add extra responses here
           data['user'] = self.user.username
           data['kind'] = self.user.kind
           data['date'] = datetime.date.today()
           return data
   

This way when you post to /api/token/ you'll get in the body something like this

{
    "access": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiZXhwIjoxNTkwOTEwNTc0LCJqdGkiOiIwM2Q5MzA1NTZmNzk0NmFjODU1MzJlNTYzNjUwZDY0MCIsInVzZXJfaWQiOjExfQ.H0huO84qtzdbo4OkKhsW_vtNTGwInG67gum6f138h1y66EiyZ1BvxaxbfEE2oPG4pB0XjiWQrXc5PlR9C6UvfQ",
    "user": "tiago",
    "kind": "whatever_this_has"
    "date": "2020-05-31"
}