Create a payjoin FAQ

[yashrajd]

FAQ for payjoin.org.

Need to identify audience and scope. Might have to change assignee.

[DanGould]

Back and Forth questions with Daniel Nordh

What is required to ‘accepts bip21 payjoin uri’s’?

Yes, anything listed on https://bitcoinqr.dev/ can read bip21. payjoin's bip 21 "pj" is an parameter that could be ignored if the wallet doesn't fully support payjoin. It would automatically fall back to regular on-chain or lightning.

Do we know which products and common libraries already do?

Would you say that Payjoin adoption among wallets is a binary case, i.e unless all (or most) common wallets adopt it, it won’t really work? As in, if I as a sender is trying to send with Payjoin to someone who uses a wallet that doesn’t support it, will normal expected behaviours fail?

Not at all. Payjoin only needs a few key players to enable the potential to payjoin to make the basis of heuristic on-chain surveillance obsolete. If there is a significant probability a normal looking transaction is a payjoin, following coins, that probability compounds when following a history and identifying clusters, which becomes significantly less certain. I'm happy to go into detail on any of these issues if you'd like.

Might be useful to have a ‘todo-list’ for wallet’s that want to support it. (I.e. what do I need to do/add/build)The requirement for a server component might hold back some adoption I imagine.

I thought that todo list was at the top of the page following the “Read the SDK docs” link, but you’re the second person to ask for it. Did you click either? Maybe it needs to be on the main page insteadAgree on the server being a roadblock. That’s a solved technical issue that will require some projects to take a chance on an integration. I guess I haven’t released a demo video for the working proof of concept serverless payjoin yet :thinking_face:

Aha, I didn’t click through to the SDK readme on first pass.One way of making sure more developers can enable this easily going forward might be to look into BDK integrations? I’ve been using BDK but in Swift and Flutter. Getting it integrated at the Rust level would save you effort of making packages for every platform.

I Agree. Here are two examples of that exact BDK x Payjoin dev kit combination for you. First, working in https://bitmask.app/ on web app + extension here and second in early draft for foundation devices Envoy (Swift and Flutter). Clearly this info needs a signal boost in pixels on the page.

[DanGould]

up at payjoin.org