Replace By Fee (RBF)
A Bitcoin node policy (BIP125) allowing an unconfirmed transaction to be replaced by a new one that pays a higher fee.
- Acronym
- RBF
- Also known as
- RBF
Replace By Fee (RBF) is a Bitcoin mempool policy that lets an unconfirmed transaction be replaced by a conflicting version that pays a higher fee. The replacement spends at least one of the same inputs, so miners are incentivized to confirm the higher-fee version instead.
BIP125 defines opt-in RBF signaling, where the original transaction marks itself replaceable using sequence numbers. Some node policies also allow broader replacement behavior. Wallet support and exchange handling vary, so users should not assume every unconfirmed transaction is final.
RBF improves fee management but weakens assumptions around zero-confirmation acceptance. A receiver who delivers goods before confirmation may be exposed if the sender replaces the transaction with one paying a different recipient.
Related terms
7 linkedExplore connected entries beyond the alphabetical index.
Mempool
→A temporary storage space in a node for pending transactions that have not yet been included in a confirmed block.
Fee
→A transaction fee is the amount paid for block inclusion, compensating block producers and discouraging spam.
Fee Rate
→A fee rate is the transaction fee per unit of size, such as satoshis per vbyte, used to prioritize block inclusion.
Transaction
→A signed data message that asks a blockchain to transfer value, execute code, or update state.
Double Spend
→A double spend is an attempt to spend the same coins twice by getting one conflicting transaction accepted over another.
Zero Confirmation
→A transaction that has been broadcast but not yet included in a block, so it has zero confirmations.
Bitcoin Improvement Proposal (BIP)
→A design document proposing changes or standards for Bitcoin.
All terms and definitions may update as the Cryptionary improves.
