Opt-in RBF
policy · mempool · fees
BIP125 signaling that marks an unconfirmed Bitcoin transaction as replaceable under opt-in relay policy.
- Also known as
- opt-in replace-by-fee, BIP125 signaling
Opt-in RBF is a Bitcoin convention in which a transaction uses a sequence number below the final thresholds described by BIP125 to signal that a higher-fee conflict may replace it. Descendants can inherit replaceability from an unconfirmed ancestor.
Signaling does not force every node or miner to accept a replacement, and lack of signaling does not guarantee that no replacement will propagate. Full-RBF policies ignore the opt-in distinction while still applying replacement fee and anti-spam rules.
Wallet interfaces should distinguish an RBF fee bump from child-pays-for-parent and from cancelling a payment. A replacement is a new transaction spending conflicting inputs; it does not edit a confirmed transaction.
Related terms
Replace By Fee (RBF)
→A mempool policy that can accept a conflicting unconfirmed transaction when the replacement satisfies fee and relay rules.
bitcoin · policy · fees
Mempool
→A node's local set of unconfirmed transactions accepted for possible relay and block inclusion.
blockchain · node
Fee Rate
→Transaction fee per unit of size: commonly sat/vB for Bitcoin or sat/byte for Bitcoin Cash. It helps explain miner selection, not a guaranteed wait.
blockchain · economics
Zero Confirmation
→A transaction observed before any block has included it.
transaction · security
Transaction
→A serialized state transition that a blockchain can validate, relay, and include in a block.
blockchain · technical