Lightning Network

How it works#

Connect your LND node and a Bitcoin Lightning tile appears on checkouts. Choosing it:

1. Checks your node's incoming channel capacity when the macaroon allows it - if there is not enough remote balance to route the payment, the buyer is told immediately instead of paying into a dead invoice (with an invoice-only macaroon the check is skipped and the invoice itself decides)
2. Creates a BOLT-11 invoice for the satoshi amount (priced off the on-chain BTC rate)
3. Shows the payment request and QR code; settlement is detected by polling the invoice directly on your node - from the buyer's browser and by a server-side sweep, so a closed tab never strands a paid order

Settlement is instant: a paid Lightning invoice completes the transaction with zero confirmations - no block wait, no confirmation threshold.

Setup#

1. Open Settings → Nodes & Testnet (requires the wallets permission)
2. Under Bitcoin Lightning Network, set your node URL in full form (e.g. https://lnd.yourdomain.com or https://lnd.yourdomain.com:8443 behind a reverse proxy); a bare hostname still defaults to https:// and the LND port 8080
3. Paste your LND macaroon hex - the invoice.macaroon is enough (least privilege: it can create and query invoices, nothing else) and it is stored encrypted
4. Optionally add extra headers (e.g. Grpc-Metadata-macaroon) if your node sits behind a proxy
5. Turn Lightning active on

Running it well#

• Inbound liquidity is the constraint. Keep enough remote balance on your channels for your typical sale size; U.CASH emails you when a payment had to be refused for insufficient remote balance
• HTTPS with a valid certificate is required - the connection to your node verifies TLS, and settlement verification fails closed: if your node cannot be reached, orders are never marked paid
• Lightning runs alongside on-chain BTC; buyers pick their rail from the two tiles
• Fees: Lightning payments settle to your node; you pay only channel costs - there is no platform surcharge for the rail