BIP 174 — Partially Signed Bitcoin Transaction Format

BIP 174 (Partially Signed Bitcoin Transaction Format) defines PSBT, a standard container for passing an unsigned or partially signed transaction between wallets, hardware signers, and coordinators, each adding the data or signatures it can. It is the interoperability backbone of hardware-wallet and multisig workflows. Repository status: Deployed.

Debate relevance: Comes up in self-custody best-practice debates (air-gapped signing, multisig coordination) and in vendor-lock-in arguments. Common misstatements: Older references list BIP 174 as 'Proposed' — current repository status is Deployed. A PSBT is not a signed transaction and cannot be broadcast until finalized; 'sending someone a PSBT' moves no funds by itself.