Replace by Fee

Replace by Fee (RBF) is a tool within the Bitcoin protocol, developed by well-known blockchain developer Peter Todd, that allows for the replacement of one version of an unconfirmed transaction with another transaction that offers a higher transaction fee. With RBF, unconfirmed transactions are stored in the mempool, the pool of valid transactions awaiting confirmation on the Bitcoin network. These transactions can be replaced if the sender of a new transaction offers a higher fee. While RBF can alleviate network congestion and prioritize transactions based on fee preference, its use has generated controversy due to its impact on transaction immutability.