[quesera]

Payment card networks have delegated authorization plans, where if a major processor goes down, they will still route transactions and use a simplified secondary network for making approval decisions.

It's called "stand-in processing", and I assume it's the inspiration here.

[4ndrewl]

The Monzo example feels different though, as they're explicitly not looking to replicate all functionality, just something minimal to get by whilst they fix the primary cloud services.