BOLT 11

BOLT 11 is the specification for Lightning invoices - the encoded payment requests that begin with lnbc (mainnet) or lntb (testnet). It's one of the BOLT specs that define how Lightning implementations interoperate.

A BOLT-11 invoice encodes everything a payer needs to complete a payment:

• Amount (optional - the payer can specify if the invoice doesn't).
• Payment hash - hash of the secret preimage that, when revealed, completes the payment.
• Destination node public key.
• Routing hints for nodes that aren't well-connected to the public graph (useful for mobile wallets).
• Expiry - default 1 hour.
• Optional description / memo.
• A signature from the recipient's node, proving it created the invoice.

The whole thing is encoded as bech32 - the same address format used for native SegWit addresses. The result is a relatively short string that fits in a QR code and can be copy-pasted, scanned, or NFC-tapped.

Single-use by design. Once the payment hash is revealed (when the payment settles), reusing the same invoice would either fail or be a fraud signal. To accept recurring payments at one fixed handle, you need BOLT-12 offers (the modern successor) or a separate invoice-per-payment workflow.

BOLT-11 has been Lightning's payment-request lingua franca since 2017. Every Lightning wallet supports it. BOLT-12 is gradually displacing it, but BOLT-11 will be in heavy use for many years yet.