Identifying Replacement-By-Fee (RBF) Transactions in Bitcoin Core

As a Bitcoin enthusiast, monitoring the mempool for specific transaction patterns can be valuable for analyzing network behavior, optimizing node performance, or even identifying potential issues with the blockchain. One such pattern is the Replace-By-Fee (RBF) mechanism, which allows miners to update their transactions on-chain without incurring a re-mempooling fee. However, this feature requires a methodical approach to identifying cases where a transaction in the mempool uses RBF.

What is Replacement-By-Fee (RBF)?

In Bitcoin Core, RBF is a mechanism that allows miners to update their transactions before they are included in the next block. When a miner adds a new transaction to the mempool, it must be verified by other nodes before it is accepted into the blockchain. If the added transaction is considered invalid or does not contain enough fees, it will be rejected and a re-mempooling fee will be charged. However, if the transaction meets the requirements, it can be added to the next block without triggering re-mempooling.

Is there a Bitcoin Core method to identify RBF transactions in the mempool?

To identify transactions that use RBF, you will need to use a combination of manual analysis and programming. One method is to save current transactions to the mempool and compare them with newly added transactions. Here is an example code snippet in Python:

import requests
def check_rbf_transactions(mempool_url):









Initialize lists to store RBF transactions
rbf_transactions = []

Run through all transactions in mempool
for transaction mempool.get_transaction_list():

Check if transaction uses RBF (Replace-by-Fee)
if transaction.get('rbf'):

Add RBF transaction to list
rbf_transactions.append(transaction['data'])
return rbf_transactions

Usage example:
mempool_url = '
rfb_transactions = check_rbf_transactions(mempool_url)
print("RBF transactions:")
if transaction i is enumerate(rbf_transactions) in the field:
print(f"Transaction {i+1}: {transaction['data']}")

This code snippet uses the Bitcoin API to retrieve mempool transactions and check RBF transactions. The “check_rbf_transactions” function takes a URL to the mempool as input and returns a list of RBF transactions.

Manual Analysis

Alternatively, you can perform manual analysis on the mempool data by comparing individual transactions with newly added transactions. This approach requires significant manual effort, but provides accurate results. Here is an example code snippet in Python:

def check_rbf_transactions_manual(mempool_url):

Initialize lists to store RBF transactions
rbf_transactions = []

Run through all new transactions in the mempool
for i transaction in enumerate(mempool.get_transaction_list()):

Compare the current transaction with the newly added transactions
if i > 0 and all(transaction['data'] != x['data'] for x in mpool.get_transaction_list()[:i]):

Append RBF transaction to the list
rbf_transactions.append(transaction)
return rbf_transactions

Usage example:
mempool_url = '
rfb_transactions = check_rbf_transactions_manual(mempool_url)
print("RBF Transactions (Manual Analysis):")
For i, transaction in enumerate(rfb_transactions):
print(f"Transaction {i+1}: {transaction['data']}")

This code snippet compares each new transaction to all previous transactions to identify cases where the current transaction uses RBF.

Conclusion

Identifying transactions that use Replace-By-Fee (RBF) is a difficult task, but can be solved with a combination of manual analysis and programming.

Ethereum Blockchain Info Bitcoin