The merchant is another type of object you will meet working with the Pentadata API. We have a very comprehensive knowledge base, and are publishing new API endpoints very frequently.
This endpoint (available as POST /merchants/mcc) solves the painful problem of identifying the category of a business just by looking at the odd text-string that appears on a bank (or card) statement.
The API returns this information conveniently organized by MCCs (Merchant Category Codes), so that you can get a real-time understanding of your customer preferences. For an historical overview of the same data, you will probably want to use the GET /persons/:id/spendings endpoint instead.