How to enable replace-by-fee via command-line in bitcoin-core?


According to bitcoin core version 0.12.0 release notes:

It is now possible to replace transactions in the transaction memory pool of Bitcoin Core 0.12 nodes.

Transaction replacement can be disabled with a new command line option, -mempoolreplacement=0.

Note that the wallet in Bitcoin Core 0.12 does not yet have support for creating transactions that would be replaceable under BIP 125.

So the mempool can be configured to accept/reject replacement transactions, but there is not support yet for creating replaceable transactions.

Bitcoin v0.12.1 release notes do not include any modification regarding RBF.

The functionality for the wallets is split in...

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bitcoin-cli and bitcoind command line options and help

You may need to use sudo to execute these help commands as shown (eg, 'sudo bitcoin-cli --help') Bitcoin Core RPC client version v0.11.0 Usage: bitcoin-cli [options] [params] Send command to Bitcoin Core bitcoin-cli [options] help List commands bitcoin-cli [options] help Get help for a command Options: -? This help message -conf= Specify configuration file (default: bitcoin.conf) -datadir= Specify data directory -testnet Use the test network -regtest Enter regression test mode, which uses a special chain in which blocks can be solved instantly. This is intended for regression testing tools and app development. -rpcconnect= Send commands to node running on (default: -rpcport= Connect to JSON-RPC on (default: 8332 or testnet: 18332) -rpcwait Wait for RPC server to start -rpcuser= Username for JSON-RPC connections -rpcpassword= Password for JSON-RPC...
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Command Description -? This help message -alerts Receive and display P2P network alerts (default: 1) -alertnotify= Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message) -blocknotify= Execute command when the best block changes (%s in cmd is replaced by block hash) -checkblocks= How many blocks to check at startup (default: 288, 0 = all) -checklevel= How thorough the block verification of -checkblocks is (0-4, default: 3) -conf= Specify configuration file (default: bitcoin.conf) -datadir= Specify data directory -dbcache= Set database cache size in megabytes (4 to 16384, default: 100) -loadblock= Imports blocks from external blk000??.dat file on startup -maxorphantx= Keep at most unconnectable transactions in memory (default: 100) -maxmempool= Keep the transaction memory pool below megabytes (default: 300) -mempoolexpiry= Do not keep transactions in the mempool longer than hours (default: 72) -par= Set the number of script...
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A new addition to Bitcoin Core called Opt-In Replace-by-Fee allows transactions to be flagged as replaceable, and actually replaced, until the transaction gets confirmed in the next block.

Opt-In RBF is a change to the memory pool and network relay code and gives wallets the option to add a signal to transactions that gives permission for full nodes to update the particular transaction. Bitcoin creator Satoshi Nakamoto introduced transaction replacement in his initial release of the Bitcoin Software, but removed it due to denial of service problems, which opt-in RBF solves by adding a higher fee for transaction replacement.

It is a slight variation of Replace-by-Fee, another feature included in Bitcoin Core. A full analysis of RBF, written by Aaron Van Wirdum can be found here.

Peter Todd, a Bitcoin Core developer who worked on the opt-in RBF project, publicly expressed concern in a blog post that opt-in RBF wallets are not yet ready to implement detection...

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Why Bitcoin Core Won’t Sync

While bitcoin core is the original and most recognized bitcoin wallet, it is also extremely bulky and requires a ton of resources to run. With the bitcoin core wallet you have to download the entire bitcoin blockchain (over 8 years of bitcoin transactions) and keep it synced to be able to spend your bitcoin. The bitcoin blockchain is over 100 GB in size which is too large for most users to store and can still take weeks for some people to download before they can use the wallet. Many people accidentally send bitcoin to their core wallet without realizing how long it will take to sync, then decide they would like to use another wallet. This guide will help you recover your bitcoins from bitcoin core, then transfer them to a lightweight wallet that is easier to use.

How To Recover Coins From Bitcoin Core

If you have sent bitcoins to your core wallet and can’t wait to synchronize the wallet, you can export your private keys and...

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The bitcoin.conf file allows customization for your node. Create a new file in a text-editor and save it as bitcoin.conf in your /bitcoin directory.

Location of your /bitcoin directory depends on your operation system.

Windows XP C:\Documents and Settings\\Application Data\Bitcoin
Windows Vista, 7, 10 C:\Users\\AppData\Roaming\Bitcoin
Linux /home//.bitcoin
Mac OSX /Users//Library/Application Support/Bitcoin

What a typical bitcoin.conf file could look like:

rpcuser=someusername rpcpassword=somepassword rpcallowip=localhost daemon=1 prune=600 minrelaytxfee=2500 maxconnections=20 maxuploadtarget=250

Below is a list of available options and settings available per the Bitcoin source code.

-? This help message -alerts Receive and display P2P network alerts (default: 1) -alertnotify= Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message) ...
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A few days ago, I wanted to sell some bitcoins for USD on my debit card. I decided to use Paxful, as I have a well trusted buyer there, whom I have been dealing with for quite a while. So, I transferred my bitcoins to my wallet on Paxful. Surprisingly enough, the transaction was confirmed exactly 30.25 hours after initiating it, which was extremely inconvenient to me and my trading partner. Interestingly, it happened that I sent a couple of transactions after initiating the Paxful transaction, and they were both confirmed much earlier than the Paxful transaction, so why are some transactions confirmed before the others? and why do some transactions take a long time to get confirmed?

Fees versus Confirmation Delays:

Obviously, when traffic across the bitcoin network increases, confirmation delays can be expected. This usually happens during times of bullish rallies. Bitcoin price had just crossed the $1,200 mark, when I had to wait for more than 30 hours for my...

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Bitcoin is the currency of the Internet: a distributed, worldwide, decentralized digital money. Unlike traditional currencies such as dollars, bitcoins are issued and managed without any central authority whatsoever: there is no government, company, or bank in charge of Bitcoin. As such, it is more resistant to wild inflation and corrupt banks. With Bitcoin, you can be your own bank.

If you are new to Bitcoin, check out We Use Coins and You can also explore the Bitcoin Wiki:

How to buy bitcoins worldwide
Buying Reddit Gold with bitcoin

Will I earn money by mining bitcoin?

Security guide for beginners - (WIP)

Community guidelines

Do not use URL shortening services: always submit the real link. Begging/asking for bitcoins is absolutely not allowed, no matter how badly you need the bitcoins. Only requests for donations to large, recognized charities are allowed, and only if there is good reason to believe that the person...
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The answer is Replace-By-Fee.

Replace-By-Fee (RBF) is a recently reintroduced feature to allow a sender "bumping" the fee of a "stuck" transaction.

In reality, a new transaction with the same outputs and inputs is created. The only difference is that the sender is able to include a higher fee as an incentive for miners to include such transaction in a block faster.

For the purpose of the tutorial, I'll be using Electrum 2.8.2. The process should be very similar in other wallets that support RBF feature too.

Download Electrum

Before making any low-fee transaction, make sure Replace-By-Fee option is turned on.

Go to Tools -> Electrum preferences and change Propose Replace-By-Fee to Always or If the fee is low.

Say you want to try your luck paying a 0.0001 BTC fee first (just to find out it's insufficient and your transaction won't be confirmed anytime soon).

Choose the Replaceable option and send the...

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Bitcoiners may not know how to include appropriate amount of miner fees, frequently send the bitcoin payments with far less than recommended amount of fees, or forget to include it, which will lead to the stuck bitcoin payments. The money is frozen in the network. Recipients may eventually choose to drop the deals and senders are probably scare that the money is lost. As a normal bitcoin user, they don’t have any idea how to clear this payment. Since the release of Bitcoin Core in version 0.12, a new feature called Replace-by-Fee (RBF), is introduced to bitcoin protocol, which allows unaccepted transactions to be replaced with a new transaction including higher fees. This tutorial is from the bitcoin senders’ point of view to give them a better idea how to use RBF to bump up the confirmation process.

How does RBF Work?

We should make sure the wallet turns RBF on. At the time of doing bitcoin payment, the wallet software can flag it as to tell the bitcoin network that...

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Building the exchange software in-house: Gather a dedicated team of developers (friends, freelancers) to build (and maintain) your exchange software. Make sure that they understand how an exchange operates in general, how cryptocurrency and blockchain technology works, and that they implement the above-mentioned components.

From a programming language point of view, the choice of the proper language might also vary depending on which cryptocurrency you want to implement for your exchange (check out this post). Furthermore, make sure that your software is compatible with various payment processing platforms or banks to safeguard payment transactions within your exchange.

Most importantly (this is a no-brainer, but some people seem to have unrealistic expectations), you need to estimate the costs and time associated with developing, maintaining, and constantly upgrading the software in-house. Due to its inherent complex nature, developing an exchange software from...

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Bitcoin Core is a free and open source Bitcoin wallet software developed by the Bitcoin Foundation. In this tutorial we are going to look at how to install Bitcoin Core wallet on Ubuntu 16.04 and Ubuntu 16.10. Once it’s done, you will have your own bitcoin wallet address which you can use to send, receive and store bitcoins.

Installing Bitcoin Core Wallet on Ubuntu 16.04 or Ubuntu 16.10

Bitcoin Core wallet isn’t included in Ubuntu software repository, but we can easily install it from the Bitcoin Team PPA. This PPA is maintained by a Bitcoin developer named Matt Collaro and is recommended for Ubuntu users on Bitcoin Core download page.

Fire up a terminal window (


) and run the following 3 commands to add the PPA, update local package index and install Bitcoin Core wallet.

sudo add-apt-repository ppa:bitcoin/bitcoin sudo apt update sudo apt install bitcoin-qt bitcoind

bitcoin-qt provides a graphical interface, while bitcoind is the...

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There are two variations of the original bitcoin program available; one with a graphical user interface (usually referred to as just “Bitcoin”), and a 'headless' version (called bitcoind). They are completely compatible with each other, and take the same command-line arguments, read the same configuration file, and read and write the same data files. You can run one copy of either Bitcoin or bitcoind on your system at a time (if you accidently try to launch another, the copy will let you know that Bitcoin or bitcoind is already running and will exit).

Linux Quickstart

The simplest way to start from scratch with the command line client, automatically syncing blockchain and creating a wallet, is to just run this command (without arguments) from the directory containing your bitcoind binary:


To run with the standard GUI interface:


Command-line arguments

Give bitcoind the -? or –-help argument and it will print out a list of...

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Provided by:



bitcoin.conf - bitcoin configuration file


All command-line options (except for '-datadir' and '-conf') may be specified in a configuration file, and all configuration file options may also be specified on the command line. Command-line options override values set in the configuration file. The configuration file is a list of 'setting=value' pairs, one per line, with optional comments starting with the '#' character. The configuration file is not automatically created; you can create it using your favorite plain-text editor. By default, bitcoind(1) will look for a file named bitcoin.conf(5) in the bitcoin data directory, but both the data directory and the configuration file path may be changed using the '-datadir' and '-conf' command-line arguments.


bitcoin.conf should be located in $HOME/.bitcoin


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