The API view (code example below) does use a serializer. Perhaps an alternate solution could involve manually declaring a serializer attribute?

class CalculationView(APIView):    permission_classes = (IsAuthenticated,)    @swagger_auto_schema(        query_serializer=CalculationSerializer,        responses=custom_view_to_response("get", "CalculationView"),    )    def get(self, request, format=None):        param_serializer = CalculationSerializer(data=request.GET)        param_serializer.is_valid(raise_exception=True)        calculator = Calculate(param_serializer.data)        calculator.init()        data = calculator.call()        return Response(data)

Thanks for the example. As you do not setresource_name in your view I assume that the data returned bycalculator.call() is already in JSON:API spec format. Is this correct?

I think in such a case where theAPIView is manually building the result it should also manually format the errors. For this you can overwritehandle_exception of your view and use the utilityrest_framework_json_api.utils.format_error_object with a fix pointer to attributes when the exception is a singleValidationError or otherwise call super. I haven't tested this but should work in theory.