Replace-by-fee (RBF)
Also · RBF · Fee bumping
Replace-by-fee lets a sender replace an unconfirmed Bitcoin transaction with a new version paying higher fees, so a stuck payment can be unstuck.
Replace-by-fee is a relay policy that lets a sender re-broadcast an unconfirmed transaction with a higher fee. Nodes that accept the replacement drop the old version from their mempool. It is the standard way to rescue a payment sent with fees that turned out too low.
Whether a replacement is relayed depends on each node’s policy, not on consensus. Bitcoin Core 28.0 made full-RBF the default, meaning replacements are accepted even when the original did not signal for it. For merchants, the lesson is older than that setting. A transaction with 0 confirmations can always be replaced.
In French · Replace-by-fee (RBF)