Hi @littlejim, you shouldn't worry about that for several reasons.

1. They are regulated by the FCA, all client funds are in a segregated bank account at Lloyd's & Barclays, which are safeguarded by the FCA.
2. They have 1.5 Million Customers, they make millions every month, closing the app would be the most stupid thing ever. Whenever you pay with your Revolut card, Revolut gets a percentage from the merchant, this is how they make money.
3. They already applied for a Banking License, it is just a matter of time until they get it.