Looking on docs.monzo.com, the “https://api.monzo.com/transactions” API call should return the balance at the time of the transaction, but I’ve never been able to retrieve this information. The transactions it returns gives the value of the transaction, but not the balance at the time of the transaction.
Is there any way to retrieve this? Or am I going to have to go through each and every transaction, doing a running total?
Unfortunately we don’t currently support this. (The balance field dates from the Prepaid days.)
A running balance is complicated by the fact that the amount on a transaction can change after the fact. The most common example is foreign card transactions, where the amount will change when the transaction settles, due to exchange rate fluctuations.