I found the spent ‘today’ when travelling to be confusing. I’m in Boston for the past few days, and was surprised when my spend today included last nigts meal. (yep I know its not a massive problem)
To do this better the spend today needs to reflect local Timezone. To do this Monzo needs to track the prior 24hours worth of Timezones that the App is in or use data from card present transactions. If the user has been in the same Timezone for prior 24 hours this is the timezone that should be used to calculate the daily spend (and presnt all transactions in)
If the user has been in 2 or more Timezones in prior 24 hours things are more complicated. You can pick the Timezone that gives the longest ‘day’ (Ie the one in which 1AM was longest ago) the most current timezone, or instead of ‘today’ calculate prior 24hr spend.
It is right that all transactions are logged and recorded in UTC. however the transactions can be more meaningful when presented based on the local timezone. The iphone automatically switches timezone - So I dont see why Monzo should behave differently.