There's no single best cashback credit card — there's the best card for how you actually spend. Pull your last three statements, sort by category, and match the top two categories to a bonus card.
For everyday spending
Citi Double Cash and Wells Fargo Active Cash both pay a flat 2% back on every purchase. These are the workhorse cards you use whenever no bonus card applies.
For grocery-heavy households
Amex Blue Cash Preferred pays 6% back at U.S. supermarkets on up to $6,000 a year in spending. For a family that spends $500/month on groceries, that's $360 a year back on food alone — enough to cover the annual fee three times over.
For dining and streaming
Capital One Savor pays 4% on dining and streaming with no annual cap. Chase Sapphire Preferred (technically points, not cashback) is a strong alternative if you value transferable travel rewards.
For gas and warehouse clubs
Costco Anywhere Visa pays 4% on gas, 3% on dining and travel, 2% at Costco. Sam's Club Mastercard pays 5% on gas and 3% on dining. Both require paid warehouse memberships.
For online shopping
Amex Blue Cash Preferred pays 3% on online retail. Bank of America Customized Cash lets you pick online shopping as your 3% category. Both stack cleanly on top of a portal click-through.
For rotating categories
Chase Freedom Flex and Discover it both pay 5% on rotating quarterly categories (Amazon, gas, grocery, dining) up to $1,500 per quarter. Set a calendar reminder to activate every three months — miss the activation and the quarter earns 1%.
Most shoppers hit diminishing returns after two cards: one flat-rate 2% card as the default, one category-bonus card that covers your top spending category. Everything else is optimization theater.