Yes, cashu.me has it as an experimental feature. It's been implemented in backends mostly. The upcoming BTCPayServer plugin by nostr:nprofile1qqsdmcml9nhl7q59zxm0t4xjx9zsryp3kxkqn7dvkazlszqg9psd5xgpzemhxue69uhhyetvv9ujuurjd9kkzmpwdejhgqgjwaehxw309ac82unsd3jhqct89ejhxqgnwaehxw309aex2mrp09skymr99ehhyec7nx7m9 supports it.
Discussion
yeah without that it forces me to attempt to melt to accept it, if I knew every token was from a mint I trust then I could accept payment even if the mint is down, since I trust it to come up again.
is it safe to do that with those proofs somehow?