Merchant Support Questions & Answers Where to find API username and password? You have to log in to the Merchant Portal, and under General Settings you will see API credentials. Last Updated: 11 months ago in Questions & Answers Did this article answer your question? Related Articles What is the difference between initial and standing amount? How to change email address on the payment page? What is Open Banking? What is processing account? What is EMV 3DS? What is PSD2?