What Is the Replace-by-Fee (RBF) Protocol and How Is It Activated?

Replace-by-Fee (RBF) is a protocol feature that allows an unconfirmed transaction to be replaced by a new, conflicting transaction that pays a higher fee. It is activated by the sender setting a specific flag (an RBF signal) in the original transaction before broadcasting it.

This signal indicates to the network that the sender reserves the right to replace the transaction later. Without this explicit opt-in, nodes may adhere to a "first-seen" policy, which rejects the replacement transaction.

How Does RBF Allow a User to Effectively ‘Unstick’ a Low-Fee Transaction?
How Do Replace-by-Fee (RBF) Mechanisms Help Users on a Congested Network?
What Is the Replace-by-Fee (RBF) Protocol and How Is It Activated?
Does RBF Allow a User to Change the Recipient of a Transaction?
How Does “Replace-by-Fee” (RBF) Impact a Miner’s Transaction Selection Process?
How Can a User Replace a Zero-Fee Transaction with a Higher-Fee One?
What Is a ‘Replace-by-Fee’ (RBF) Transaction?
What Is ‘Replace-by-Fee’ (RBF)?

Glossar