Works offline. Nothing leaves this device.
Your tax numbers for every country, ready to read out at the counter.
The registry failed to load. Serve this folder over http:// rather than opening the file directly, or check that the registry/ directory is intact.
This browser is not letting the page store anything, so cards will disappear when you reload. A private window or blocked site data is the usual cause.
Your cards
No card yet
Add one and it stays on this device — nothing is ever sent anywhere.
No analytics, no sync, no account, no error reporting. The only things this page asks the network for are its own files from this domain, and not one request carries anything you typed.
Cards live in this browser, on this device only. Clearing site data deletes them, and no other device or browser can see them.
Some numbers are refused outright. A US Social Security Number and a Japanese My Number are never stored — the card editor explains why and what to use instead.
Coverage: every ISO 3166 jurisdiction is present — 249 in all. {t1} are verified against their authority, {t2} carry published structure, and the rest store and present without validating. Each card says which.