Ask HN: Anyone on HN built their own Credit card transaction analyzer?

So many practitioners of personal finance on HN so I figured I would ask here. Has anyone built up their own credit card transaction analyzer?

I was thinking of something that would take the transaction downloads from a credit card portal in csv. And analyze the transactions by category. So for travel, airfare etc.

It could learn from categorizations (names of restaurants).

Hypothetically, what would you use for this? Something like NLTK paired with pandas?

Happy to listen to others who have tried something similar.

(Not using Mint, have tried it and didn't want to link my bank accounts, just my credit cards)