Abstract: A system and method for recommending portable financial device for a payment transaction is disclosed. The method includes establishing a secure communication session with one or more external APIs during a payment transaction stage and fetching data representative of banking accounts associated with a customer from the one or more external APIs. The method further includes determining one or more transactional parameters associated with the payment transaction stage and generating an optimal score for each of the one or more portable financial devices by using Machine Learning (ML) based transaction model. The method includes identifying best suitable portable financial device with maximum optimal score and recommending the identified best suitable portable financial device for completing the payment transaction stage based on the identification.