Which of the given cards earns the most at a store (merchant) or for a spend category, today. Returns the card, the honest rate, why, and caveats (merchant-code traps, activation, ties). Base rates + rotating bonuses + built-in card benefits only; a user's personal bank offers live on their phone and are not consulted here.

The store's reward category as RightCard's directory files it, its merchant type, and the merchant-code caveat when a category bonus usually will not post there (superstores like Walmart/Target, warehouse clubs like Costco/Sam's). Same ranking the app uses.

Search RightCard's catalog by card or issuer name to get the ids to pass into best_card. Verified cards first; unverified cards are flagged, never hidden.

Everything RightCard knows about one card: rates by category, base rate, currency, annual fee, verification status, live rotating windows, and the choose-your-category spec if it has one.

Live and upcoming rotating-category windows (Freedom Flex, Discover it, Citi Dividend…) and permanent merchant benefits, from the same verified data as the app. Optionally filter by card id.