Tapwhich
The card to tap here, and why.
Tapwhich tells you which of your cards to tap here, why, and up to what cap. Pick a place and the cards you hold; the answer names the card, the rate, the cap and the second best.
Sample answer
Grab, 250,000 VNDUse VPBank Z JCB here, because Grab is a bonus merchant: 15% back, up to 500,000 VND this statement.
You earn 37,500 VND. Second best: UOB One, 10% back, 25,000 VND, up to 600,000 VND this statement.
From VPBank's and UOB's own pages, read 11 Oct 2026.
How it picks
Each card in the pack is a list of rules written from the bank's own page: a merchant list or a category, the card network codes (MCC), a country, online or in a shop, and start and end dates. Tapwhich keeps the rules that fit the place, checks any minimum spend, takes the tightest cap, adds a promotion that stacks, and takes off a foreign fee abroad. The card that leaves you the most money wins; on a tie, the one that needs fewer assumptions.
When it has to assume something, such as a statement spend you did not give, it says so under the answer. A check re-reads every bank page the pack cites every 6 hours, and readers can report a rule as wrong. When a page changed, a program proposes the update and the answer says "changed, verifying" until a person confirms it; when readers doubt a rule too, the answer also hides its cap. Every answer says when its rule was last checked. The full method is on the Tapwhich method page.
For AI agents
Agents call pick_card on https://tapwhich.openkrill.app/mcp with the place and the cards, plus an optional amount in any currency the pack has a rate for. The result carries the same one line, every card ranked with its cap and conditions, and the bank link with its read date.
Frequently asked questions
Which cards and countries does Tapwhich cover?
The first pack covers 23 cashback and points cards from 12 banks in Vietnam. The app reads one pack per country, so another country is a new pack, not a new app.
Does Tapwhich know my card number or my spending?
No. You pick card names from a list. Your cards, bonus picks and statement spend stay in your own browser, and there is no account.
Can the answer be wrong?
Yes, in two ways it says out loud. The shop's bank sets the code (MCC) a purchase reports, so a shop can land in another category. And banks change offers, so every answer shows the date its bank page was read and links to that page.