offer amount description [issuer] [label] [quantity_min] [quantity_max] [absolute_expiry] [recurrence] [recurrence_base] [recurrence_paywindow] [recurrence_limit] [single_use]
Note that it creates two variants of the offer: a signed and an unsigned one (which is smaller). Wallets should accept both: the current specification allows either.
The amount parameter can be the string "any", which creates an offer that can be paid with any amount (e.g. a donation). Otherwise it can be a positive value in millisatoshi precision; it can be a whole number, or a whole number ending in msat or sat, or a number with three decimal places ending in sat, or a number with 1 to 11 decimal places ending in btc.
amount can also have an ISO 4217 postfix (i.e. USD), in which case currency conversion will need to be done for the invoice itself. A plugin is needed which provides the "currencyconvert" API for this currency, otherwise the offer creation will fail.
The description is a short description of purpose of the offer, e.g. coffee. This value is encoded into the resulting offer and is viewable by anyone you expose this offer to. It must be UTF-8, and cannot use JSON escape codes.
The issuer is another (optional) field exposed in the offer, and reflects who is issuing this offer (i.e. you) if appropriate.
The label field is an internal-use name for the offer, which can be any UTF-8 string.
The present of quantity_min or quantity_max indicates that the invoice can specify more than one of the items within this (inclusive) range. The amount for the invoice will need to be multiplied accordingly. These are encoded in the offer.
The absolute_expiry is optionally the time the offer is valid until, in seconds since the first day of 1970 UTC. If not set, the offer remains valid (though it can be deactivated by the issuer of course). This is encoded in the offer.
recurrence means that an invoice is expected at regular intervals. The argument is a positive number followed by one of "seconds", "minutes", "hours", "days", "weeks", "months" or "years" (variants without the trailing "s" are also permitted). This is encoded in the offer. The semantics of recurrence is fairly predictable, but fully documented in BOLT 12. e.g. "4weeks".
recurrence_base is an optional time in seconds since the first day of 1970 UTC, optionally with a "@" prefix. This indicates when the first period begins; without this, the recurrence periods start from the first invoice. The "@" prefix means that the invoice must start by paying the first period; otherwise it is permitted to start at any period. This is encoded in the offer. e.g. "@1609459200" indicates you must start paying on the 1st January 2021.
recurrence_paywindow is an optional argument of form start of a period in which an invoice and payment is valid, the second time is the number of seconds after the start of the period. For example -604800+86400 means you can fetch an pay the invoice 4 weeks before the given period starts, and up to 1 day afterwards. The optional % indicates that the amount of the invoice will be scaled by the time remaining in the period. If this is not specified, the default is that payment is allowed during the current and previous periods. This is encoded in the offer.
recurrence_limit is an optional argument to indicate the maximum period which exists. eg. "12" means there are 13 periods, from 0 to 12 inclusive. This is encoded in the offer.
refund_for is the payment_preimage of a previous (paid) invoice. This implies send_invoice and single_use. This is encoded in the offer.
single_use (default false) indicates that the offer is only valid once; we may issue multiple invoices, but as soon as one is paid all other invoices will be expired (i.e. only one person can pay this offer).
On failure, an error is returned and no offer is created. If the lightning process fails before responding, the caller should use lightning-listoffers(7) to query whether this offer was created or not.
If the offer already existed, and is still active, that is returned; if it's not active then this call fails.
The following error codes may occur: