How is a payjoin coordinated between different wallets? Can a payjoin happen between sparrow and mutiny?
Basically, payjoin is a way to coordinate multiple users inputs and outputs into one transaction? Is there a way for participants of payjoins to select inputs and outputs?
Payjoin is coordinated by end to end encrypted messages transmitted over the internet between sender and receiver. The protocol is specified in BIP 78 and BIP 77. Neither sparrow nor Mutiny support receiving payjoin yet (but stay tuned)
Payjoin enables exactly what you’ve described, multiple inputs and outputs from each user may be batched into a single transaction. Input selection depends on the wallet implementation but is not limited by the payjoin protocol itself. What selection do you have in mind?
Okay cool, I think I get it.
As far as selection goes, the more options the better. The use case I have in mind is for transactions at Bitcoin meetups. A large single transaction could be built coordinating many of the transactions taking place at the meetup simultaneously.
For example, I sell maple syrup from one individual and buy coffee from another. This could be one payjoin transaction? Could the participants in the transaction choose to consolidate utxos as well?
How does signing work? Would the users be looking at the same payjoin transaction on each of their wallets and hit send at the same time?
I’m not sure of any UI that yet enables this fine grained queueing and batching you’re describing but it’s certainly possible. sender would propose their batch, receiver would respond with theirs, combined and signed, and the sender would take a final sign off if all looks good. Should be the same flow you’re used to for any other tx in terms of signing, but both would set up queues or batches in their respective wallets beforehand to consolidate or otherwise batch funds beforehand. nostr:npub1yashrajtj3ddn9u2ypzalp4qew4f9u8wls0tpf5kuvqarenqwckql8adnu might have some design input
