Replace by fee (RBF)
Replace by fee is a Bitcoin transaction replacement mechanism that can allow an unconfirmed transaction to be replaced by another version offering a higher fee.
✦ Key Insight
RBF can help users respond when a Bitcoin transaction was sent with a fee that is too low for current network conditions.
✕ Common Misconceptions
RBF works on unconfirmed transactions and is not a method for reversing a transaction that has already been confirmed.
Detailed Explanation
In Practice
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Confirmation
A confirmation indicates that a transaction has been included in a block and has gained additional blockchain history after it.
Mempool
A mempool is a node's temporary pool of valid, unconfirmed transactions waiting to be included in a block.
sat/vB
sat/vB means satoshis per virtual byte and is a common unit for expressing the fee rate of a Bitcoin transaction.
Child pays for parent (CPFP)
Child pays for parent is a Bitcoin fee-bumping technique where a high-fee child transaction incentivizes miners to confirm it together with its low-fee unconfirmed parent.
UTXO
A UTXO is an unspent transaction output that represents a discrete amount of cryptocurrency available to be used as an input in a future transaction.