Check yourself: Receive without a till

Questions and answers, readable without JavaScript.

1. What is a BOLT-11 invoice?

   • A reusable Bitcoin address with a Lightning prefix
   • A channel opening request
   • A signed, time-bounded request for funds, with a payment hash — one shot
   • An LNURL by another name
   Answer 1

   A signed, time-bounded request for funds, with a payment hash — one shot

   BOLT #0 calls an invoice a request for funds so the payer can later prove payment. The note's frame: it is a signed, time-bounded request, not a reusable address.

   Read the note → · Receive-Only Lightning Is Not a Merchant Stack

2. What makes a correct invoice still unpayable?

   • No inbound capacity on the receive side. Generating invoices is cheap; being reachable is not free
   • A Bech32 checksum
   • Omitting the lightning: prefix
   • Using uppercase in a QR
   Answer 2

   No inbound capacity on the receive side. Generating invoices is cheap; being reachable is not free

   Inbound liquidity is how many sats a channel can still accept. An invoice with zero inbound capacity is an unpayable request, however correct the checksum looks.

   Read the note → · Receive-Only Lightning Is Not a Merchant Stack

3. What does a sticky LNURL-pay QR actually encode?

   • A permanent payment hash
   • A URL that mints a fresh invoice. The invoice itself stays single-use
   • Your on-chain xpub
   • A BOLT-12 offer
   Answer 3

   A URL that mints a fresh invoice. The invoice itself stays single-use

   BOLT-11 invoices expire and are typically single-use. LNURL-pay's sticky QR encodes a URL that returns a fresh Bech32 invoice, not a permanent payment hash.

   Read the note → · Receive-Only Lightning Is Not a Merchant Stack