Hi, I don't believe the XSF should maintain a registry of payment schemes or systems or specific proof types for payment schemes. This is not our field of expertise and this should be happening elsewhere. I understand with RFC 8905 there is already some standard and a corresponding registry and we could entirely rely on that (or any other open standard with a suitable registry) instead of doing our own. I also would want to refrain to include any specific crypto-currency network or technology in a specification document, because else there will be a ton of stuff to specify: The industry site CoinMarketCap lists more than 150 "Layer 1" crypto-currencies and "competition" in the industry is largely about being mentioned in some "official" sounding documents, so soon everyone will want to have a XEP if we open that can of worms. There's also a very unhelpful part where you say that currency is ISO 4217 or non-ISO code. That makes it effectively "put anything here". The part where the amount field also includes the currency code is also weird to me (usually we would want to use our XML syntax instead of a custom syntax), but that's a minor. So my suggestion is to mostly piggy-back on top of RFC 8905 (or any other suitable open standard specification) and have lighting or whatever cryptocurrency network you want to support be integrated with those people that actually do know payments much better than the XSF. Marvin On Fri, 2026-04-24 at 10:26 +0000, Daniel Gultsch wrote: