PSBT: prepare and sign Bitcoin transactions offline
Understand the coordinator, offline signer and broadcaster, and verify destinations before moving a signed transaction online.
The quick answer
A partially signed Bitcoin transaction, or PSBT, packages a proposed transaction and signing information. A coordinator prepares it; compatible signers add approvals before finalization and broadcast.
Offline keys still need trustworthy verification
An air gap reduces direct connectivity, but files and QR codes still carry untrusted data. The signer's trusted display and recognized wallet policy matter more than trusting the coordinating computer.
Step by step
- 1
Prepare with compatible software
Select inputs and set the recipient and fee. Export a PSBT version and transport format your signer supports. Keep recovery words off the coordinator.
- 2
Inspect on the signer
Verify the full recipient, amount, fee and recognized change. Reject unexpected outputs or an unrecognized wallet policy before adding your signature.
- 3
Finalize and broadcast
Return the signed data through the documented route. Gather all required signatures, finalize the transaction and verify the resulting transaction ID after broadcast.
Worked example
A watch-only laptop prepares a payment; a hardware device signs it offline. In a 2-of-3 wallet, one signature is still insufficient to authorize spending.
Before you continue
A related question
Is a PSBT already on the blockchain?
No. Preparation and signing happen before a finalized transaction is broadcast. Broadcast alone still does not mean confirmation.
Try it with a tool
Sources & further reading
Source links checked on 15 Oct 2026. Examples explain the mechanics; provider fees and features can change.
- BIP 174 github.com
- Sparrow Wallet sparrowwallet.com
