My primary bank, Monzo (UK) provides a full API and trigger webhook for events.

This has enabled me to make a WhatsApp bot that asks me to explain abnormal transactions (using an LLM for reasoning), and also have a pre-midnight sweep balance to savings account to maximise interest daily interest.

I also maintain a small daily balance, and if I spend money during the day it tops it up from the savings to maintain that low balance. If I need to spend more, I can move money manually.

That's so awesome! You should open source this. Wish we had this in the US, would make things so much easier.