'\" t
.\"     Title: lightning-pay
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 03/16/2018
.\"    Manual: \ \&
.\"    Source: \ \&
.\"  Language: English
.\"
.TH "LIGHTNING\-PAY" "7" "03/16/2018" "\ \&" "\ \&"
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.SH "NAME"
lightning-pay \- Protocol for sending a payment to a BOLT11 invoice
.SH "SYNOPSIS"
.sp
\fBpay\fR \fIbolt11\fR [\fImsatoshi\fR] [\fIdescription\fR] [\fIriskfactor\fR] [\fImaxfeepercent\fR] [\fIretry_for\fR]
.SH "DESCRIPTION"
.sp
The \fBpay\fR RPC command attempts to find a route to the given destination, and send the funds it asks for\&. If the \fIbolt11\fR does not contain an amount, \fImsatoshi\fR is required, otherwise if it is specified it must be \fInull\fR\&. If \fIbolt11\fR contains a description hash (\fIh\fR field) \fIdescription\fR is required, otherwise it is unused\&. The \fIriskfactor\fR is described in detail in lightning\-getroute(7), and defaults to 1\&.0\&. The \fImaxfeepercent\fR limits the money paid in fees, and defaults to 0\&.5\&. The \(oqmaxfeepercent\(cq is a percentage of the amount that is to be paid\&.
.sp
The \fBpay\fR RPC command will randomize routes slightly, as long as the route achieves the targeted \fImaxfeepercent\fR\&.
.sp
The response will occur when the payment fails or succeeds\&. Once a payment has succeeded, calls to \fBpay\fR with the same \fIbolt11\fR will succeed immediately\&.
.sp
The command will keep finding routes and retrying the payment until it succeeds, or the given \fIretry_for\fR seconds passes\&. Note that the command may stop retrying while a pending payment is ongoing, which you need to monitor with \fBlistpayments\fR or \fBwaitsendpay\fR\&. \fIretry_for\fR defaults to 60 seconds and can only be an integer\&.
.sp
When using \fIlightning\-cli\fR, you may skip optional parameters by using \fInull\fR\&. Alternatively, use \fB\-k\fR option to provide parameters by name\&.
.SH "RETURN VALUE"
.sp
On success, this returns the payment \fIpreimage\fR which hashes to the \fIpayment_hash\fR to prove that the payment was successful\&. It will also return, a \fIgetroute_tries\fR and a \fIsendpay_tries\fR statistics for the number of times it internally called \fBgetroute\fR and \fBsendpay\fR\&.
.sp
On error, if the error occurred from a node other than the final destination, the route table will be updated so that getroute(7) should return an alternate route (if any)\&. An error from the final destination implies the payment should not be retried\&.
.sp
The following error codes may occur:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\-1\&. Catchall nonspecific error\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
200\&. Payment timed out while a payment is in progress\&. Monitor the status of that payment with
\fIlistpayments\fR
command, or wait for that payment to complete with
\fIpay\fR
command\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
201\&. Already paid with this
\fIhash\fR
using different amount or destination\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
203\&. Permanent failure at destination\&. The
\fIdata\fR
field of the error will be routing failure object\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
205\&. Unable to find a route\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
206\&. Route too expensive\&. The
\fIdata\fR
field of the error will indicate the actual
\fIfee\fR
as well as the
\fIfeepercent\fR
percentage that the fee has of the destination payment amount\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
207\&. Invoice expired\&. Payment took too long before expiration, or already expired at the time you initiated payment\&. The
\fIdata\fR
field of the error indicates
\fInow\fR
(the current time) and
\fIexpiry\fR
(the invoice expiration) as UNIX epoch time in seconds\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
210\&. Payment timed out without a payment in progress\&.
.RE
.sp
Error codes 202 and 204 will only get reported at \fBsendpay\fR; in \fBpay\fR we will keep retrying if we would have gotten those errors\&.
.sp
A routing failure object has the fields below:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIerring_index\fR\&. The index of the node along the route that reported the error\&. 0 for the local node, 1 for the first hop, and so on\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIerring_node\fR\&. The hex string of the pubkey id of the node that reported the error\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIerring_channel\fR\&. The short channel ID of the channel that has the error, or
\fI0:0:0\fR
if the destination node raised the error\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIfailcode\fR\&. The failure code, as per BOLT #4\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
\fIchannel_update\fR\&. The hex string of the
\fIchannel_update\fR
message received from the remote node\&. Only present if error is from the remote node and the
\fIfailcode\fR
has the UPDATE bit set, as per BOLT #4\&.
.RE
.sp
The \fIdata\fR field of errors will include statistics \fIgetroute_tries\fR and \fIsendpay_tries\fR\&. It will also contain a \fIfailures\fR field with detailed data about routing errors\&.
.SH "AUTHOR"
.sp
Rusty Russell <rusty@rustcorp\&.com\&.au> is mainly responsible\&.
.SH "SEE ALSO"
.sp
lightning\-listpayments(7), lightning\-decodepay(7), lightning\-listinvoice(7), lightning\-delinvoice(7), lightning\-getroute(7), lightning\-invoice(7)\&.
.SH "RESOURCES"
.sp
Main web site: https://github\&.com/ElementsProject/lightning