How a crypto QR code works
The code holds a payment URI that wallet apps understand. For Bitcoin it follows the BIP-21 format: bitcoin:bc1qexampleaddress?amount=0.0015&label=Coffee%20stand. The scheme names the coin, followed by your address and, optionally, the amount in coins and a short label of up to 60 characters. Litecoin, Dogecoin, Bitcoin Cash and Solana use the same pattern with their own scheme.
For Ethereum, the code contains only ethereum: and the address. Wallets handle Ethereum amounts in different ways, so the amount is left for the sender to type.
The code is meant to be scanned from inside a wallet app, using its scan or send button. The phone's camera may also recognize it and offer to open an installed wallet. The wallet then shows the address and amount for review; nothing is sent until the sender confirms.
Where it helps
- A shop that accepts Bitcoin displays a code at the register, so customers do not have to copy a 42-character address by hand.
- A creator adds a donation code for a Solana or Litecoin wallet to the end of a video or a printed zine.
- A conference booth shows a code with a fixed amount for a ticket or merchandise payment.
- Someone receiving a transfer from a friend shows the code on their screen instead of sending the address through a chat app.
Tips before you print
- Double-check the address character by character against your wallet. Crypto transfers cannot be reversed, and a wrong address means lost funds.
- Make sure the coin matches the wallet. Sending one coin to an address for another network can lose the funds.
- Amounts are in coins, not dollars, with up to eight decimal places. Since prices move, leave the amount empty for anything printed to last.
- Consider using a dedicated receiving address. Anyone who scans a public code can look up that address's history on the blockchain.