In‑store Lightning POS

Hardware options

Networking & node

• Dedicated POS Wi‑Fi/VLAN with QoS; restrict internet access to necessary endpoints.
• Choose a managed gateway or your own node; monitor inbound liquidity and uptime.
• Keep an LTE hotspot for failover; test regularly.

Cashier workflow

1. Enter amount (fiat); system calculates sats with live FX.
2. Show Lightning invoice QR and countdown; customer scans and pays.
3. Upon confirmation, POS shows Paid and emits a receipt.
4. Close order and proceed to fulfillment.

Receipts that build trust

• Include order id, fiat & sats, timestamp, and proof link (payment hash explorer or your receipt portal).
• Offer SMS/email receipt and printable ticket; avoid embedding raw addresses.

Refunds & under/over‑pays

• For under‑pay: allow top‑up within the invoice window; otherwise cancel and recreate.
• For refund: collect return invoice or on‑chain address securely; log proof of refund.

Offline & degraded mode

• When Lightning is unavailable, fall back to on‑chain for higher‑value sales with clear fee/time expectations.
• If internet is down, switch to LTE hotspot or issue an IOU QR that customers can pay later (use with caution).

Security & roles

• Restrict POS user roles; require manager PINs for refunds and settings.
• No seeds on POS devices; use gateway tokens with least privilege.
• Lock screens and enable remote wipe for mobile devices.

Testing checklist

• Tiny test payments; expired invoice handling; refund flow end‑to‑end.
• Receipt shows proof link and matches the order.
• Failover to LTE hotspot and back without losing orders.

Troubleshooting

• Invoice not updating → check network, node status, and webhook delivery logs.
• Slow payments → verify inbound liquidity, consider MPP, or route via better peers.
• Printer issues → test ESC/POS config; keep digital receipt fallback.