5.2: Resending a Transaction with RBF

NOTE: This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.

If your Bitcoin transaction is stuck, and you're sender, you can resend it using RBF (replace-by-fee).

VERSION WARNING: This is an innovation from Bitcoin Core v 0.12.0, which means that by now most miners should be using it. However, it only reached full maturity in the Bitcoin core wallet Bitcoin Core v 0.14.0.

Opt-In for RBF

RBF is an opt-in Bitcoin feature. Transactions are only eligible for using RBF if they've been created with a special RBF flag. This is done by setting their sequence number (which is typically set automatically, so that it's more than 0 and less than 0xffffffff (4294967295).

This is simply done by adding a sequence variable to the vins:

$ rawtxhex=$(bitcoin-cli -named createrawtransaction transactions='''[ { "txid": "'$utxo_txid'", "vout": '$utxo_vout', "sequence": 1 } ]''' outputs='''{ "'$recipient'": 2.9, "'$changeaddress'": 1.0 }''')

You should of course sign and send your transaction as usual:

$ signedtx=$(bitcoin-cli -named signrawtransaction hexstring=$rawtxhex | jq -r '.hex')
$ bitcoin-cli -named sendrawtransaction hexstring=$signedtx
4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6

Now, when you look at your transaction, you should see something new: the bip125-replaceable line, which has always been marked no before, is now marked yes:

$ bitcoin-cli gettransaction 4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6
{
  "amount": -2.90000000,
  "fee": 0.00000000,
  "confirmations": 0,
  "trusted": true,
  "txid": "4075dbf84303c01adcb0b36cd2c164e2b447192c2d9fbf5fde3b99d0ac7e64b6",
  "walletconflicts": [
  ],
  "time": 1491597044,
  "timereceived": 1491597044,
  "bip125-replaceable": "yes",
  "details": [
    {
      "account": "",
      "address": "n2eMqTT929pb1RDNuqEnxdaLau1rxy3efi",
      "category": "send",
      "amount": -2.90000000,
      "vout": 0,
      "fee": 0.00000000,
      "abandoned": false
    }
  ],
  "hex": "020000000100e3da9fa8b5368dd383ebabb820ae257d8f19bb1a9e3fb36f6c3e1b83e6d0f3000000006b483045022100950af7346a5bff5546627b6e9379573cb7e56420d6187f90a8b7aab8fcad730502200c4e66b96b499fec020f9397861bda765c29ec873fc8e61f85a32c73e650173b0121031008e55d06d25bb2acdf85395fe4c2df28492325d8ffc3734a2dc372436b6a330100000002800c4911000000001976a914e7c1345fc8f87c68170b3aa798a956c2fe6a9eff88ac00e1f505000000001976a914d83b41b8f67b31310bb487b66d859a6d0a92682c88ac00000000"
}

The bip125-replaceable flag will stay yes until the transaction receives confirmations. At that point it is no longer replacable.

Should I trust transactions with no confirmations? No, never. This was true before RBF and it was true after RBF. Transactions must receive confirmations before they are trustworthy. This is especially true if a transaction is marked as bip125-replaceable, becausethen it can be ... replaced.

Optional: Always Opt-In for RBF

If you prefer, you can always opt in for RBF. Do so by running your bitcoind with the -walletrbf command or simply adding it to your bitcoin.conf file:

walletrbf=1

Once you've done this (and restarted your bitcoind), then all transactions should have a lower sequence number and be marked as bip125-replaceable.

VERSION WARNING: The walletrbf flag require Bitcoin Core v.0.14.0.

Replace a Transaction the Hard Way: By Hand

Use RBF Wisely

-low to high transaction fees -combine transactions

It doesn't solve the same problem. Core devs are looking for compressing transactions, not necessarily adding fees alone.

Replace a Transaction the Easy Way: By bumpfee

VERSION WARNING: The bumpfee RPC require Bitcoin Core v.0.14.0.

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