Great to see self-custodial wallet with PoS mode since Breez is no more supported and Misty Breez lack the PoS.

Ideally a good merchant Bitcoin PoS should have:

- Keypad

- Items list

- Discount input

- Tips input

- Tax management

- Easily extractable accounting, like in csv

- easy access to last invoice pending or paid, to double check that an invoice was paid properly and show it to the customer if it failed.

- employee mode (invoice only), ideally usable from multiple separate devices, for each employee or each cash point.

- refund management (ideally locked to work only from manager device or with a PIN)

- Contactless boltcards support

- Bolt12 support for paying using a fixed QR code sticker

- Onchain support as an opt-in option (that can be limited for amount above a certain level), zero conf as opt-in. (If you have to pay for an hotel, or service, waiting some hours for confirmations is not issue, of course for paying ice cream you want Lightning only.

Also I would love that Lightning wallets could have a mode with a short timeout, like if payment is not confirmed within 15 or 30sec, you get a failed payement screen and you are 100% sure that it can never get confirmed beyond the timeout. Sats stays at customer wallet (or get auto-refund).

This is one of biggest downside and main serious issue I had while paying with Lightning for a couple of years. PoS give a timeout or just quit the invoice and then payement pass 10min later while another invoice was paid (possibly not in Bitcoin), then you figure it out when you are away from merchant that you paid twice for your goods. Not sure if this can be solved by PoS wallet only, customer wallet, both or if changes must be done at the Lightning protocol level. But this must be solved for Bitcoin mass adoption.