What Is ‘Replace-by-Fee’ (RBF)?
Replace-by-Fee (RBF) is a feature that allows a sender to replace an unconfirmed transaction in the mempool with a new version of the transaction, provided the new version pays a higher fee. This is used to speed up transactions that are stuck due to a low initial fee.
Glossar
Unconfirmed Transaction
Transaction ⎊ An unconfirmed transaction is a cryptographically signed instruction to transfer value that has been broadcast to the peer-to-peer network but has not yet been included in a validated block by a miner or validator.
RBF
Policy ⎊ RBF (Replace-by-Fee) is a protocol feature that allows a user to replace an unconfirmed transaction in the mempool with a new transaction that includes a higher transaction fee.