[Last Updated: 17 January 2022.]
Since late-2020, the level of Bitcoin transaction activity is such that there can be extended periods of time that it will exceed the supply of space in new blocks on the Bitcoin blockchain.
Transactions compete to be included in the next block solved by a miner based on the amount of the Bitcoin network transaction fee that the transaction offers to pay. Transactions whose transaction fee offer isn’t competitive enough will sit in the mempool, waiting for miners to clear out the transactions that had paid a higher fee.
Being able to bump up the transaction fee on a transaction is useful to help rescue a time-sensitive transaction, or as a strategy to pay less in fees. If your wallet supports replace-by-fee (RBF), and that support is enabled for a transaction, you can feel comfortable choosing the lower-end of the transaction fee range. If the transaction doesn’t confirm soon enough for you, you can simply bump the fee later using RBF.
The wallets with RBF support (that I know of):
- Bitcoin Core has RBF support, including in the GUI (where an unconfirmed transaction offers the option to select “Increase transaction fee”).
- Blockstream Green has RBF support built-in now
- Electrum lets you right click, and then increase the fee, which uses RBF. There’s also a “Cancel” transaction, which uses RBF (as-of Electrum v4.0.4).
- Samourai Wallet (Android) (enabled in Settings > Transactions menu)
- BlueWallet has RBF support implemented as “Bump Fee” and “Cancel Transaction”
- Specter Wallet has RBF support
- Moonshine (iOS and Android) has RBF support
- Coinb.in will let you create a transaction with RBF enabled and separately will let you create a replacement transaction. [Caution: This is a powerful, low-level tool and it lets you make a mistake that could result in you losing your funds.]
- ConIO has RBF support
- Nunchuk (Beta) has RBF support
- Armory, reportedly does, per a comment reply to an r/Bitcoin post
- Founder of Hodl Wallet had tweeted that RBF was “on the roadmap”
Hardware wallets with RBF:
Non-custodial exchange wallets with RBF:
- HodlHodl lets you do RBF on the escrow funding transaction.
- LocalCryptos lets you do RBF on both the escrow funding as well as for wallet withdrawal transactions.
Custodial/online wallets with RBF:
- Blockstream’s Bitcoin Explorer where you can find additional information about your transaction, including the fee offered (sats/vByte)
- Mempool / fee estimation sites: Mempool.space, Johoe’s Bitcoin Mempool Statistics, Bitcoiner.Live Fee, and BitcoinFees.net
- Bitcoin Optech’s RBF in the Wild article
- Chart — Transactions Using RBF. Just because you are using a wallet with RBF support doesn’t mean your transactions are marked as replaceable. Only when the transaction is marked as replaceable when first sent can a replacement transaction be relayed later. As-of March, 2021 only about 17% of Bitcoin transactions are marked as replaceable. [Update: As the New Year 2022 arrived, that metric was closing in on 30%.]
- Replace-By-Fee article on the Bitcoin wiki
- Fee Bumping article on the Bitcoin wiki, which includes info on Child-Pays-For-Parent (CPFP) as well. Unlike with RBF, CPFP fee bumping can be done if you are the recipient of the funds as well
- Opt-in RBF FAQ
- Choosing a wallet? There are nearly two dozen wallets listed on Bitcoin.org
- A Guide to Saving on Bitcoin’s High Transaction Fees