OPRTN OPRTN is a Bitcoin-only, self-custodial Android wallet. Your keys are generated and stored on your device. There is no account, no signup, no custodian, and no telemetry. Write a message onto Bitcoin. Any transfer can carry a short message, written into an OP_RETURN output. Once the transaction is mined that message is part of the blockchain — it cannot be edited and it cannot be deleted. OPRTN also reads messages back off any transaction that carries one, including transactions sent by other people. Wallets: legacy, SegWit and Taproot, plus multisig and watch-only. Connect to your own Electrum server or Bitcoin node. Coin control and fee bumping. Encrypted storage with plausible deniability. On-chain only. There is no Lightning in this wallet.