Django REST Framework Serializers - object-level validation

DRF tip:

You can use object-level validation to validate fields in comparison to one another.

For example:

class MovieSerializer(serializers.ModelSerializer):
    class Meta:
        model = Movie
        fields = '__all__'

    def validate(self, data):
        if data['us_gross'] > data['worldwide_gross']:
            raise serializers.ValidationError(
                'us_gross cannot be bigger than worldwide_gross'
        return data

For more, review Custom Data Validation.