Crypto Payment QR Generator

A payment QR is nothing more than a URI encoded as an image. Each network has its own scheme. Bitcoin and Litecoin use BIP-21, written as bitcoin:address?amount=0.5&label=Invoice. Ethereum uses EIP-681, where the amount goes in wei under the value parameter. Solana Pay follows an equivalent structure with the solana: scheme. The wallet scanning the code reads the URI and fills in the send form for you.

The only field every wallet handles consistently is the address. The optional parameters — amount, label and message — depend on the implementation: some wallets display them, some silently ignore them and some accept only the amount. That is why an amount encoded here is a suggestion, not an obligation, and whoever pays can change it before signing.

Amount conversion uses exact arithmetic. On Ethereum, a value of 1.5 ETH is encoded as 1500000000000000000 wei using big integers rather than floating point, so no rounding error shows up in the final digits. On Bitcoin the amount stays as decimal BTC, which is what BIP-21 expects.

Before the code is generated, the address goes through the same validator as the dedicated tools: Base58Check or Bech32 checksums on Bitcoin, and the EIP-55 checksum on Ethereum. On Solana and Litecoin only the shape is checked, and the interface says so explicitly rather than implying a guarantee the code cannot make. A well-formed QR does not turn a wrong address into the right one: always review the destination before sharing it.