LIGHTNING-SENDPAY(7)
====================
:doctype: manpage

NAME
----
lightning-sendpay - Protocol for sending a payment via a route.

SYNOPSIS
--------
*sendpay* 'route' 'hash'

DESCRIPTION
-----------

The *sendpay* RPC command attempts to send funds associated with the
given 'hash', along a route to the final destination in the route.

Generally, a client would call getroute(7) to resolve a route, then
use *sendpay* to send it.  If it fails, it would call getroute(7)
again to retry.

The response will occur when the payment fails or succeeds.  Once a
payment has succeeded, calls to *sendpay* with the same 'hash' will
fail; this prevents accidental multiple payments.

RETURN VALUE
------------

On success, a 'preimage' hex string is returned as proof that the
destination received the payment.  The 'preimage' will SHA256 to the
'hash' given by the caller.

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.

The following error codes may occur:

* -1. Catchall nonspecific error.
* 200. A previous *sendpay* or *pay* is in progress.
* 201. Already paid with this 'hash' using different amount or
  destination.
* 202. Unparseable onion reply. The 'data' field of the error
  will have an 'onionreply' field, a hex string representation
  of the raw onion reply.
* 203. Permanent failure at destination. The 'data' field of
  the error will be routing failure object.
* 204. Failure along route; retry a different route. The 'data'
  field of the error will be routing failure object.

A routing failure object has the fields below:

* 'erring_index'. 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.
* 'erring_node'. The hex string of the pubkey id of the node
  that reported the error.
* 'erring_channel'. The short channel ID of the channel that
  has the error, or '0:0:0' if the destination node raised
  the error.
* 'failcode'. The failure code, as per BOLT #4.
* 'channel_update'. The hex string of the 'channel_update'
  message received from the remote node. Only present if
  error is from the remote node and the 'failcode' has the
  UPDATE bit set, as per BOLT #4.

AUTHOR
------
Rusty Russell <rusty@rustcorp.com.au> is mainly responsible.

SEE ALSO
--------
lightning-listinvoice(7), lightning-delinvoice(7),
lightning-getroute(7), lightning-invoice(7).

RESOURCES
---------
Main web site: https://github.com/ElementsProject/lightning