FAQ
short answers to common questions.
What buyers ask most often about the cards, the apps and running a card business with the kit.
01The product
Do I need a server or Firebase?
No. The apps talk directly to public blockchain endpoints and to the APIs you add keys for. Card Studio runs on one computer. The only thing you host is the card domain with a few static files (Card host setup).
Do I hold my users' funds?
No. The kit is non-custodial. Keys stay on the user's phone (NFC Crypto) or on the user's card (CryptoCard Wallet). You never see them.
Is the card a hardware wallet?
No. It does not sign anything. In NFC Crypto it is a second factor that opens the app and confirms payments, and it can carry a PIN-encrypted backup. In CryptoCard Wallet it carries the encrypted phrase, which the phone opens for a moment to sign. See Security.
Can a card be copied?
Yes. NTAG215 and NTAG216 cards can be copied by whoever holds them. The PIN still protects the backup, but can be guessed offline, so use 8 digits or more. Copy-proof cards (NTAG 424 DNA) are not supported by this version.
Which cards should I buy?
NXP NTAG215 or NTAG216. NTAG213 is too small for a backup. MIFARE Classic does not work with iPhones. See Requirements.
Is there a web version?
No. NFC needs a phone, so the wallets are iOS and Android apps. The web/ folder in apps/nfc_crypto is not a supported target.
Do the apps work on the iOS simulator?
They run and show their screens, but simulators have no NFC, so no card can be read.
02Cards and roles
Are spending limits enforced on the blockchain?
No. They are enforced by the app on the phone where the cards are paired. Another wallet app with the same recovery phrase ignores them. See What roles and limits are not.
Can a Spender card pay with tokens?
No. Spender limits cover only the network's own coin (ETH, POL, BNB, AVAX, SOL, BTC). Tokens, swaps and dApp requests always need an Owner or Backup card.
Do all four apps understand the same card?
Yes. NFC Crypto, CryptoCard Wallet, NFC Recovery and Card Studio read the same records. A card written by one can be read by the others, as long as each app accepts the card's host. See Card format.
What happens if a user loses the only card?
In NFC Crypto, the user turns the card requirement off with three words of the recovery phrase, or waits 72 hours. The wallet itself is on the phone. In CryptoCard Wallet the phrase lives on the card, so the user needs a backup card or the written recovery phrase. Tell users to keep their phrase.
Do I need a reader to start?
No. Card Studio has a simulated reader, and the phones can pair blank cards themselves. You need an ACR122U reader to program cards in bulk before shipping.
03Business
How can I earn with the kit?
The code has one revenue mechanism: an optional swap fee on 0x, 1inch and Jupiter swaps, off by default and capped at 2 % (Swap fee). You can also sell branded cards and build white-label versions for clients; payments for those are outside the kit.
Can I use the default domain and bundle IDs?
For testing only. For anything you publish, use your own card domain, bundle IDs, Apple team and signing keys (White label).
Does the kit include card printing or a shop?
No. Cards, printing, a reader, hosting, store accounts and API keys are not included (full list).
Can I see it before buying?
Yes, in the live demo: nfccrypto-demo.mikodes.com. It runs on sample data with simulated card taps; nothing is signed, written or sent.