Monzo and Revolut alerted customers of an outage due to a processing migration from a third party processor which caused customers to be unable to use cards for transactions; other digital banks affected by the third party processor migration included Starling Bank, Loot, Curve, Pockit and Uaccount; Monzo and Revolut have both reported they will reimburse customers for foreign exchange costs incurred as a result of the outage; Monzo says it has plans to move its processing to an internal unit with transactions processed on the firm’s technology. Source
