Our customers reasonably expect to be able to spend on their card, make bank transfers and pay their bills 24 hours a day, 365 days a year. Their lives don’t have downtime for maintenance so nor should we. We dedicate a lot of our engineering effort to minimise the risk of downtime during technical migrations and other day-to-day operations, but unforeseen incidents that cause unexpected outages are impossible to eliminate entirely.

We take reliability seriously at Monzo so we built a completely separate backup banking infrastructure called Monzo Stand-in to add another layer of defence so customers can continue to use important services provided by us.…