Sorry if this has already been suggested but I’ve had a brief look and can’t find anything!
Would be really cool if you had some sort of budgeting tool, so you could see how much you have left to spend per day. So for example, I intend to use my Mondo account for all cash payments during the month (ie not rent or bills) and I want to see how much I have to spend per day. So, I top it up with say £500 on payday, and it tells me that I have £16.67 to spend per day until next payday. Then if I spend less than that the amount will increase, and if I spend more then it decreases.
It’s a really useful trick I used with my current account and think I could be great for Mondo!