Hey Product Hunt! 👋 I built this after realizing I'd been leaving serious money on the table for years. Had a Rakuten account, had good credit cards — but was never using them together strategically. The problem: cashback portal rates change daily, and the best portal for Nike today might not be the best tomorrow. On top of that, different cards give bonus % at different stores. Figuring out the optimal combo manually meant opening 4-5 tabs every time. So I built a calculator. Pick your cards, pick a store, enter the amount — it shows you which portal is paying the most right now and which card to stack on top. Completely free, no account needed. Rates update automatically every day. Would love feedback from heavy portal users — definitely still missing some edge cases and card combinations. What would make this more useful for you?

CashbackStacker

Stack portals, cards & coupons to maximize every purchase

Stack portals, cards & coupons to maximize every purchase