I don’t blame you re the third party - I wouldn’t either. I generally download a transaction file periodically and import it locally using the app. I think you’re going to find it difficult to find an API that will allow little people access, even though they are obviously happy to offer that to the big companies. Some of the brokerages have checking accounts and it might be possible to pull the transaction data via the brokers API (maybe), but whichever way you look at it, I suspect the most pragmatic solution is probably going to be a download/import of some kind.