Replace-by-Fee (RBF) is a Bitcoin protocol feature that allows users to modify an unconfirmed transaction by increasing its fee, helping it get prioritised by miners. This is useful when a transaction gets stuck due to low fees or network congestion. With RBF, the sender can essentially "replace" the original transaction with a new version that offers a higher fee, improving the chances of faster confirmation.

How RBF Works
A user broadcasts a transaction with RBF enabled.

If the transaction remains unconfirmed, the sender creates a new version with a higher fee.

Miners prioritise the updated transaction, dropping the original one.

Wallets That Support RBF
Electrum (Desktop) – One of the first to implement RBF.

Wasabi Wallet (Privacy-focused) – Supports RBF for better transaction flexibility.

Samourai Wallet (Mobile) – Offers RBF and other advanced Bitcoin tools.

Bitcoin Core (Full node wallet) – Allows manual RBF through its console.

BlueWallet (Mobile/Lightning) – Supports RBF for on-chain transactions.

Limitations & Risks
Not all wallets support RBF (e.g., many exchange wallets don’t).

Some merchants may reject RBF-enabled transactions due to double-spend risks.

RBF is a powerful tool for optimising Bitcoin transactions, especially during high-fee periods. Always check if your wallet supports it before relying on it.

Replace-by-Fee (RBF) is a Bitcoin protocol feature that enables users to increase the transaction fee of an unconfirmed transaction, improving its chances of being included in the next block. This functionality proves particularly valuable during periods of network congestion when miners prioritise transactions with higher fees.

Key Characteristics of RBF:

Requires explicit opt-in during initial transaction creation

Allows fee adjustment while the transaction remains unconfirmed

Helps accelerate stuck transactions

Maintains the same recipient address and transaction amount

Supported Wallets:

Desktop: Electrum, Bitcoin Core

Mobile: Samourai Wallet

Privacy-focused: Wasabi Wallet

Important Considerations:

Not all wallets or services accept RBF transactions

Some merchants may require additional confirmations for RBF-enabled payments

Always verify wallet compatibility before relying on this feature

RBF provides valuable flexibility for Bitcoin users, though its implementation varies across wallet providers.