B

Bitcard

A gift of bitcoin. No Bitcard app or account required.

1

Get your 12 words

Write them on the card's blank "your half" lines. Each tap makes a fresh set, so do not tap again once you have written them down.

2

Double-check what you wrote

Re-type the 12 words exactly as they appear on the card. This proves the card can unlock the bitcoin later.

3

Add bitcoin, seal, give

Send the gift from your own wallet to the address below. When the check underneath says the payment is confirmed, seal the words and give the card.

How much to put on. Satoshis ("sats") are tiny units of bitcoin. A transaction fee is deducted when the card is claimed, and it rises and falls with how busy bitcoin is: a few hundred sats when quiet, several thousand when busy. Put at least 50,000 sats on the card to be comfortable in any conditions. Below roughly 20,000 the card can be temporarily unclaimable during a busy spell. Nothing is lost when that happens, it waits for fees to drop.
1

Enter the words from the card

Both sets of 12 words are on the back of the card. Type each set in the order it appears.

Before you scratch: do this on your own phone, somewhere private. Once the panel is off it stays off, and anyone who sees or photographs both sets of words can take the bitcoin.
2

Send it to your wallet

In your wallet or exchange, choose Bitcoin (BTC) and select its native on-chain Bitcoin network, then copy the receiving address. This app cannot send through payment channels, token networks, or other blockchains. A Bitcoin address may begin with bc1, 1, or 3.

Check the balance

You only need the 12 handwritten words. Keep the panel sealed. Type them in order, with a space between each word.

Security and privacy
Advanced technical details
How the key is split. We make the 12 words under the scratch panel, so treat us as knowing that half. The other 12 words are made on your own device and we never see them. Both halves are needed to spend, so our half on its own is worth nothing, and that is the point of the design.
What the two servers see. To check a balance and to send, this app talks to two public bitcoin servers (blockstream.info and mempool.space). They cannot move your bitcoin and never see your words or your name. They do see the card's address, your device's internet (IP) address, and, when you send, the wallet address you are sending to. Before this app will move anything, both servers must report the same balance: if they disagree or one is unreachable it refuses to sign rather than guess, so an outage at either one stops this app until it clears. Your bitcoin is unaffected by that, and the offline tool needs no servers at all.
Being straight about checking this app. The fingerprint below is worked out by this page itself, and the value you would compare it against is published on our site. If someone had replaced this page they could change both, so this catches an accident or a damaged copy, not a determined attacker. The check that actually holds is not depending on our website at all: the offline tool contains no network code and hands the key to a wallet app you already trust.
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