I shipped a NuGet package, then rewrote it completely. Here's why.

If you work in fintech and process card transactions, you've seen MCC codes. Merchant Category Code- a four-digit number that tells you what kind of business charged the card. 5411 is a grocery store. 5812 is a restaurant. 7995 is a casino. Every product that touches transactions eventually needs to turn these codes into something a human can understand. Cashback rules, spend controls, analytics dashboards, compliance reports- they all need the same thing: given a code, what category is this? I'