A relay policy that permits an unconfirmed transaction to be replaced by a fee-paying conflict.
Replace-by-fee (RBF) meaning
Replace-by-fee helps a sender increase the effective fee of a transaction that is confirming too slowly. A replacement spends at least one of the same inputs, changes transaction details, and must meet node policy requirements.
How it works in Bitcoin
Wallets can construct a higher-fee replacement, commonly by reducing change or adding an input. Nodes evaluate the new transaction and may relay it in place of the original. Miners still decide which valid transaction to include.
A simple example
A sender broadcasts a 5 sat/vB payment, then network demand rises. Their wallet replaces it with a 15 sat/vB version paying the same recipient and less change back to the sender.
Why Replace-by-fee (RBF) matters
Transaction terms matter whenever bitcoin moves. Understanding them reduces mistakes involving fees, confirmation status, change outputs and irreversible destinations.
What people often get wrong
RBF only concerns unconfirmed transactions. Review the replacement carefully: poorly designed fee bumps can alter recipients or expose wallet links.
Quick checks before using the term
- Is the transaction only broadcast or already confirmed?
- Which outputs and fee are being created?
- Can wallet policy replace or delay it?
Apply these questions to the concrete example above. A precise answer is more useful than repeating the definition without naming the actor, rule or failure path.
Check the primary reference
This entry is written in plain English, but the technical source is available when you need exact protocol detail.
BIP 125: Replace-by-Fee ↗