Concepts

Amounts

All amounts are integers in zatoshi (zat). 1 ZEC is 100000000 zat. An invoice amount must be from 1 to 2100000000000000 zat.

The accountant CSV export is the exception. It shows ZEC amounts as exact decimal strings with 8 digits.

Invoice lifecycle

An invoice has one of five statuses.

Status	Meaning	Final
pending	The invoice exists and no payment is seen yet.	No
detected	A payment is seen in the mempool or in a mined block.	No
paid	The mined payments add up to at least the invoice amount.	Yes
underpaid	A mined payment exists, the sum is below the amount, and the invoice expired.	Yes
expired	The invoice expired with no payment that counts.	Yes

The normal path is pending, then detected, then paid.

A final status can still change. A late top-up that brings the total to the amount turns underpaid or expired into paid.

Confirmation

An invoice is paid after one confirmation. A confirmation takes about 75 seconds. A payment that Lunaz sees in the mempool is detected in seconds.

Lunaz does not handle chain reorgs. See Limitations.

Overpayment and underpayment

Payments to one address add up. A buyer can pay the difference before the invoice expires.

• overpaid_zat is the received amount minus the invoice amount, or 0. You refund an excess yourself.
• If the invoice expires with a mined payment that is too small, the status is underpaid. You refund the buyer yourself.

Lunaz cannot refund a payment because it cannot spend.

Expiry

You set the lifetime of an invoice with expires_in_secs. The default is 900 seconds. Lunaz limits the value to the range 60 to 86400 seconds.

An invoice that is detected from the mempool only, and has been expired for more than 1 hour, becomes expired. The transaction was probably dropped.

If a cross-chain swap is active and the invoice expires within 10 minutes, Lunaz extends the expiry to 30 minutes from the swap request. This gives the swap time to finish.

API access

Access	Endpoints
API key	Create an invoice.
Public, by invoice ID	Read an invoice, WebSocket status, swap assets, start a swap.

Everything else, such as your account, webhooks, export and withdrawals, is in the dashboard. See Authentication.