How do you get programmatic access to your data?
However, most banks do send alert emails when something is charged to a credit/debit card. Meli connects to your inbox read-only via OAuth (Google and Microsoft) or IMAP for other providers and reads those emails on your Mac.
Of course there are limitations to this approach, you only get access to the data that is available in those emails like merchant, amount, date and account.
Which banks are you interested in? Are you based in the US?