Interface SendonionRequest

The onion is specific to the route that is being used and the payment_hash used to construct, and therefore cannot be reused for other payments or to attempt a separate route. The custom onion can generally be created using the devtools/onion CLI tool, or the createonion RPC command.

The onion parameter is a hex-encoded 1366 bytes long blob that was returned by either of the tools that can generate onions. It contains the payloads destined for each hop and some metadata. Please refer to [BOLT 04][bolt04] for further details.

The first_hop parameter instructs Core Lightning which peer to send the onion to. It is a JSON dictionary that corresponds to the first element of the route array returned by getroute. The following is a minimal example telling Core Lightning to use any available channel to 022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59 to add an HTLC for 1002 millisatoshis and a delay of 21 blocks on top of the current blockheight:

{
  "id": "022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59",
  "amount_msat": "1002msat",
  "delay": 21,
}

If the first element of route does not have "channel" set, a suitable channel (if any) will be chosen, otherwise that specific short-channel-id is used.

The payment_hash parameter specifies the 32 byte hex-encoded hash to use as a challenge to the HTLC that we are sending. It is specific to the onion and has to match the one the onion was created with.

The label parameter can be used to provide a human readable reference to retrieve the payment at a later time.

The shared_secrets parameter is a JSON list of 32 byte hex-encoded secrets that were used when creating the onion. Core Lightning can send a payment with a custom onion without the knowledge of these secrets, however it will not be able to parse an eventual error message since that is encrypted with the shared secrets used in the onion. If shared_secrets is provided Core Lightning will decrypt the error, act accordingly, e.g., add a channel_update included in the error to its network view, and set the details in listsendpays correctly. If it is not provided Core Lightning will store the encrypted onion, and expose it in listsendpays allowing the caller to decrypt it externally. The following is an example of a 3 hop onion:

[
    "298606954e9de3e9d938d18a74fed794c440e8eda82e52dc08600953c8acf9c4",
    "2dc094de72adb03b90894192edf9f67919cb2691b37b1f7d4a2f4f31c108b087",
    "a7b82b240dbd77a4ac8ea07709b1395d8c510c73c17b4b392bb1f0605d989c85"
]

If shared_secrets is not provided the Core Lightning node does not know how long the route is, which channels or nodes are involved, and what an eventual error could have been. It can therefore be used for oblivious payments.

The partid value, if provided and non-zero, allows for multiple parallel partial payments with the same payment_hash.

The bolt11 parameter, if provided, will be returned in waitsendpay and listsendpays results.

The destination parameter, if provided, will be returned in listpays result.

The msatoshi parameter is used to annotate the payment, and is returned by waitsendpay and listsendpays.