Partially Signed Bitcoin Transactions (PSBT)

Partially Signed Bitcoin Transactions, or PSBT, is a standard format, defined in BIP 174 in 2017, for passing an unsigned or incompletely signed transaction between wallets and devices so each can add its signature or data. Bitcoin Core has supported it since version 0.17, and it is the common language connecting hardware wallets, multisig coordinators and air-gapped signers.

Why it matters

Before PSBT, every wallet vendor invented its own way to move transactions between an online computer and an offline signer, and multisig across different vendors was fragile. PSBT standardizes the container: it carries the transaction plus the metadata each signer needs, such as which coins are spent and their derivation paths, and each participant fills in its part. The format enables air-gapped signing via QR codes or memory cards, where private keys live on a device that never touches a network, and multivendor multisig where signatures come from devices made by different manufacturers.

In the gold vs bitcoin debate

PSBT is unglamorous infrastructure with direct monetary consequences: it is what makes rigorous self-custody, including corporate-grade multisig, practical without trusting a single vendor. The gold equivalent of a spending policy, splitting authority over an asset among executives, requires vault contracts and legal enforcement. PSBT moves that authority structure into cryptography, one of the recurring themes in the argument that bitcoin's custody scales better than metal's.