In my opinion, you should write the logic in Api . According to your description, you need firstly send request to the api to get the result and then update or insert record according to this result. you have to write Sp in such a way 1st check if "if Account Number exists it should update every other field. But if Account Number does not exist, it should insert a new record."(Eg. If Exit(Query...) in such way ) this logic you have to implement in Store Procedure .