The API end point "GET /v3/merchants/{mId}/tenders" will tell us "Credit Card" for the tender name, but we're unable to find the type of credit card (visa, mastercard, etc). Is that data point available on your API somewhere? We see it on reports but are unable to find it in the API.
The tender is always credit card (or debit card). The resulting payment has a cardTransaction field. A card transaction has a field cardType. This is what you are looking for. In the Clover Android SDK, we have the possible values enumerated as,
VISA, MC, AMEX, DISCOVER, DINERS_CLUB, JCB, MAESTRO, SOLO, LASER, CHINA_UNION_PAY, CARTE_BLANCHE, UNKNOWN, GIFT_CARD, EBT;