The \fBinvoice\fR RPC command creates the expectation of a payment of a given amount of milli\-satoshi: it returns a unique token which another lightning daemon can use to pay this invoice\&.
The \fIlabel\fR must be a unique string or number (which is treated as a string, so "01" is different from "1"); it is never revealed to other nodes on the lightning network, but it can be used to query the status of this invoice\&.
The \fIdescription\fR is a short description of purpose of payment, e\&.g\&. \fI1 cup of coffee\fR\&. This value is encoded into the BOLT11 invoice and is viewable by any node you send this invoice to\&. It must be UTF\-8, and cannot use \fI\eu\fR JSON escape codes\&.
The \fIfallbacks\fR array is one or more fallback addresses to include in the invoice (in order from most\-preferred to least): note that these arrays are not currently tracked to fulfill the invoice\&.
The \fIpreimage\fR is a 64\-digit hex string to be used as payment preimage for the created invoice\&. By default, if unspecified, lightningd will generate a secure pseudorandom preimage seeded from an appropriate entropy source on your system\&. \fBIMPORTANT\fR: if you specify the \fIpreimage\fR, you are responsible, to ensure appropriate care for generating using a secure pseudorandom generator seeded with sufficient entropy, and keeping the preimage secret\&. This parameter is an advanced feature intended for use with cutting\-edge cryptographic protocols and should not be used unless explicitly needed\&.
On success, a hash is returned as \fIpayment_hash\fR to be given to the payer, and the \fIexpiry_time\fR as a UNIX timestamp\&. It also returns a BOLT11 invoice as \fIbolt11\fR to be given to the payer\&. On failure, an error is returned and no invoice is created\&. If the lightning process fails before responding, the caller should use lightning\-listinvoice(7) to query whether this invoice was created or not\&.
