Abstract: The techniques described herein relate to a method including: receiving, from a score service application executed by one or more processors and by a backend server, a request for a merchant lifetime trust score for a merchant; determining one or more calibration models of a bottom layer and one or more merchant features; generating, by the determined a machine learning model, a raw score for the merchant lifetime trust score request; generating, by the score service application, a merchant lifetime trust score based on a business rule to the raw score; and blocking, by the score service application in communication with a payment processing application executed by a frontend server, a transaction based on the merchant lifetime trust score for the merchant.