I would find an auto-top up facility using direct debit, similar to Oyster Card and others
The way it would work is that the Monzo Account holder would set a minimum balance on their Monzo Account and a fixed top-up amount. When the Monzo balance falls below the set minimum balance the Direct Debit would then draw the fixed top-up amount from the Monzo Account Holder’s other Bank Account. The same procedure could be achieved using a Debit Card.
Would you not consider paying your salary in, and then having it withdraw automatically from a pot to the main balance if it goes below a threshold?
Much easier to manage the salary and all your money in the one app 
How would the money be drawn from another bank account on demand by Monzo?
Direct Debit or Debit Card as I said
I might consider it but I do not want to which is why I suggested a process that I have encountered elsewhere.
Doh, I missed that. The problem with direct debit is that it will be effectively upto 5 working days before Monzo can be sure the transfer has actually gone through okay
As Monzo are currently looking at charging for debit card top ups and really pushing towards using faster payments to ‘top-up’ I wouldnt expect this to be something they’d be looking to do.
Love this idea and would really appreciate it.
I’m freelance so don’t have a fixed salary and use Monzo as my personal account.
Having a notification of when your account goes beneath a certain amount (that you could set?) would be a great start to this process.
Cheers.