The $1 Fee Estimator

@samouraiwallet/one-dollar-fee-estimator

This library is a Typescript port of the original Python library - The $1 Fee Estimator.

The $1 Fee Estimator is an algorithm designed to return a feerate:

• allowing the confirmation of a Bitcoin transaction by the next block,
• lower than the median feerate paid by the transactions included in the next block.

Despite its simplicity, the $1 Fee Estimator requires very few data to perform well and is less than 200 lines of code, making it easy to deploy or to implement in all programming languages.

See original README to understand how this algorithm works.

Requirements

• Node.js v16 or newer
• NPM (or yarn or pnpm)
• Synchnonized Bitcoin Core with accessible RPC

Installation

npm i @samouraiwallet/one-dollar-fee-estimator

Usage

CLI

See @samouraiwallet/one-dollar-fee-estimator-cli

Node.js

import {FeeEstimator} from '@samouraiwallet/one-dollar-fee-estimator';

let receivedFees; // variable you want to store received fee rates in

const estimator = new FeeEstimator({
    mode: 'txs', // 'txs' | 'bundles' - optional, default 'txs'
    refresh: 30, // optional, default 30 - interval in seconds, setting too low can cause unexpected errors
    rpcOptions: {
        host: 'localhost',
        port: 8332,
        username: 'rpcUsername',
        password: 'rpcPassword',
        cookie: 'path/to/cookiefile' // optionally use cookie instead of username & password
    },
    useWorker: true, // optional, default false, set to true if your want to run estimator in a worker thread to prevent blocking of main thread
    debug: true // optional, default false, set to true if you want to see debug logs
})

// handle errors emitted by FeeEstimator
estimator.on('error', (err) => {
    console.error(err)
})

// receive live fee rate updates from the FeeEstimator
estimator.on('data', (result) => {
    // fee rates and ready status received from FeeEstimator
    // object of targets and their feerates: 
    // {
    //  ready: true,
    //  lastBlock: {
    //    height: 829364,
    //    hash: "00000000000000000001f3eb6464cd19b0a8a1f3a98b1b0af83ba9b4a4c0b259",
    //    time: 1707310080,
    //  }
    //  fees: {
    //    "0.1": number,
    //    "0.2": number,
    //    "0.5": number,
    //    "0.9": number,
    //    "0.99": number,
    //    "0.999": number,
    //   }
    // }
    // `ready` field signals that the mempool of the bitcoind is synchronized
    // calculated fee rates are unreliable if ready=false
    if (result.ready) {
      // these targets are probabilities for fee rates for next block (10%, 20%, 50%, ...)
      receivedFees = result.fees;
    }
})

// or just read last fee rates directly from the estimator
if (estimator.data.ready) {
    receivedFees = estimator.data.fees;
}

// FeeEstimator will continue working until you stop it, or the process is terminated
estimator.stop()