SubmitPackage

SubmitPackage submits a package of related transactions (topologically sorted, unconfirmed parents first and the child last) for atomic validation and acceptance. Real package submission is only performed by the bitcoind backend, via the node's submitpackage RPC, which lets a zero-fee v3/TRUC parent be accepted via its fee-paying CPFP child. The btcd backend does not support submitpackage and returns an error. A neutrino light client has no mempool and cannot atomically accept a package; as a best effort it broadcasts the transactions individually and relies on a peer's 1p1c package relay, returning an unverified result (not a package-accept verdict).

Source: walletrpc/walletkit.proto

gRPC

rpc SubmitPackage (SubmitPackageRequest) returns (SubmitPackageResponse);

REST

HTTP Method	Path
POST	/v2/wallet/tx/package

Code Samples

gRPC

Javascript

const fs = require('fs');
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');

const GRPC_HOST = 'localhost:10009'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
const TLS_PATH = 'LND_DIR/tls.cert'

const loaderOptions = {
  keepCase: true,
  longs: String,
  enums: String,
  defaults: true,
  oneofs: true,
};
const packageDefinition = protoLoader.loadSync(['lightning.proto', 'walletrpc/walletkit.proto'], loaderOptions);
const walletrpc = grpc.loadPackageDefinition(packageDefinition).walletrpc;
process.env.GRPC_SSL_CIPHER_SUITES = 'HIGH+ECDSA';
const tlsCert = fs.readFileSync(TLS_PATH);
const sslCreds = grpc.credentials.createSsl(tlsCert);
const macaroon = fs.readFileSync(MACAROON_PATH).toString('hex');
const macaroonCreds = grpc.credentials.createFromMetadataGenerator(function(args, callback) {
  let metadata = new grpc.Metadata();
  metadata.add('macaroon', macaroon);
  callback(null, metadata);
});
let creds = grpc.credentials.combineChannelCredentials(sslCreds, macaroonCreds);
let client = new walletrpc.WalletKit(GRPC_HOST, creds);
let request = {
  raw_txs: <bytes>,
  sat_per_vbyte: <uint64>,
};
client.submitPackage(request, function(err, response) {
  console.log(response);
});
// Console output:
//  {
//    "package_msg": <string>,
//    "tx_results": <TxResultsEntry>,
//    "replaced_transactions": <string>,
//  }

Python

import codecs, grpc, os
# Generate the following 2 modules by compiling the walletrpc/walletkit.proto with the grpcio-tools.
# See https://github.com/lightningnetwork/lnd/blob/master/docs/grpc/python.md for instructions.
import walletkit_pb2 as walletrpc, walletkit_pb2_grpc as walletkitstub

GRPC_HOST = 'localhost:10009'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

# create macaroon credentials
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
def metadata_callback(context, callback):
  callback([('macaroon', macaroon)], None)
auth_creds = grpc.metadata_call_credentials(metadata_callback)
# create SSL credentials
os.environ['GRPC_SSL_CIPHER_SUITES'] = 'HIGH+ECDSA'
cert = open(TLS_PATH, 'rb').read()
ssl_creds = grpc.ssl_channel_credentials(cert)
# combine macaroon and SSL credentials
combined_creds = grpc.composite_channel_credentials(ssl_creds, auth_creds)
# make the request
channel = grpc.secure_channel(GRPC_HOST, combined_creds)
stub = walletkitstub.WalletKitStub(channel)
request = walletrpc.SubmitPackageRequest(
  raw_txs=<bytes>,
  sat_per_vbyte=<uint64>,
)
response = stub.SubmitPackage(request)
print(response)
# {
#    "package_msg": <string>,
#    "tx_results": <TxResultsEntry>,
#    "replaced_transactions": <string>,
# }

grpcurl

# grpcurl docs: https://github.com/fullstorydev/grpcurl
# Proto source: https://github.com/lightningnetwork/lnd
GRPC_HOST=localhost:10009
LND_DIR=~/.lnd
LND_SOURCE=path/to/lnd
NETWORK=mainnet
MACAROON_PATH="$LND_DIR/data/chain/bitcoin/$NETWORK/admin.macaroon"
TLS_PATH="$LND_DIR/tls.cert"

grpcurl \
    -import-path $LND_SOURCE/lnrpc/ \
    -proto walletrpc/walletkit.proto \
    -cacert $TLS_PATH \
    -H "macaroon: $(xxd -ps -u -c 1000 $MACAROON_PATH)" \
    -d '{ "raw_txs": BASE64_ENCODED_VALUE, "sat_per_vbyte": <uint64> }' \
    $GRPC_HOST \
    walletrpc.WalletKit/SubmitPackage

REST

Javascript

const fs = require('fs');
const request = require('request');

const REST_HOST = 'localhost:8080'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'

let requestBody = {
  raw_txs: <array>, // <bytes> (base64 encoded)
  sat_per_vbyte: <string>, // <uint64> 
};
let options = {
  url: `https://${REST_HOST}/v2/wallet/tx/package`,
  // Work-around for self-signed certificates.
  rejectUnauthorized: false,
  json: true,
  headers: {
    'Grpc-Metadata-macaroon': fs.readFileSync(MACAROON_PATH).toString('hex'),
  },
  form: JSON.stringify(requestBody),
}
request.post(options, function(error, response, body) {
  console.log(body);
});
// Console output:
//  {
//    "package_msg": <string>, // <string> 
//    "tx_results": <object>, // <TxResultsEntry> 
//    "replaced_transactions": <array>, // <string> 
//  }

Python

import base64, codecs, json, requests

REST_HOST = 'localhost:8080'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

url = f'https://{REST_HOST}/v2/wallet/tx/package'
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
headers = {'Grpc-Metadata-macaroon': macaroon}
data = {
  'raw_txs': base64.b64encode(<bytes>),
  'sat_per_vbyte': <uint64>,
}
r = requests.post(url, headers=headers, data=json.dumps(data), verify=TLS_PATH)
print(r.json())
# {
#    "package_msg": <string>,
#    "tx_results": <TxResultsEntry>,
#    "replaced_transactions": <string>,
# }

curl

REST_HOST=localhost:8080
LND_DIR=~/.lnd
NETWORK=mainnet
MACAROON_PATH="$LND_DIR/data/chain/bitcoin/$NETWORK/admin.macaroon"
TLS_PATH="$LND_DIR/tls.cert"

curl -X POST \
    --cacert $TLS_PATH \
    -H "Grpc-Metadata-macaroon: $(xxd -ps -u -c 1000 $MACAROON_PATH)" \
    -d '{ "raw_txs": BASE64_ENCODED_VALUE, "sat_per_vbyte": <uint64> }' \
    https://$REST_HOST/v2/wallet/tx/package

lncli

$ lncli wallet submitpackage --help

NAME:
   lncli wallet submitpackage - Submit a package of related transactions for atomic validation and acceptance.

USAGE:
   lncli wallet submitpackage [command options] parent_tx_hex... child_tx_hex

DESCRIPTION:
   
  Submit a package of related, topologically-sorted raw transactions
  (unconfirmed parents first and the child last) to the chain backend
  for atomic validation and acceptance via the submitpackage RPC.

  This allows a zero-fee v3/TRUC parent to be accepted via its
  fee-paying CPFP child, which a standalone broadcast would reject.
  Each argument is a hex-encoded raw transaction.
  

OPTIONS:
   --sat_per_vbyte value  (optional) the maximum fee rate in sat/vByte allowed for any transaction in the package; omit to use the node default, set 0 to disable the limit (default: 0)
   

Messages

walletrpc.SubmitPackageRequest

Source: walletrpc/walletkit.proto

Field	gRPC Type	REST Type	REST Placement
raw_txs The raw serialized transactions forming the package, topologically sorted with unconfirmed parents first and the child last.	bytes[]	array	body
sat_per_vbyte Optional per-transaction fee-rate ceiling in sat/vByte (mapped onto the submitpackage maxfeerate). When unset the node's default is used; an explicit 0 means no limit, which is required for a CPFP child whose standalone feerate is high.	uint64	string	body

walletrpc.SubmitPackageResponse

Source: walletrpc/walletkit.proto

Field	gRPC Type	REST Type
package_msg A summary message; "success" when the whole package was accepted.	string	string
tx_results Per-transaction results keyed by wtxid (hex).	TxResultsEntry[]	object
replaced_transactions The txids of transactions evicted via package RBF.	string[]	array

Nested Messages

walletrpc.SubmitPackageResponse.TxResultsEntry

Field	gRPC Type	REST Type
key	string	unknown
value	SubmitPackageTxResult	unknown

walletrpc.SubmitPackageTxResult

Field	gRPC Type	REST Type
txid The transaction id (txid) in hex.	string	string
error If non-empty, the reason this transaction was rejected.	string	string
other_wtxid If non-empty, the wtxid (in hex) of a transaction with the same txid but a different witness that was already in the mempool; the submitted transaction was ignored as a duplicate (witness replacement).	string	string