Client-side Bitcoin JavaScript library

npm install bitcoinjs-lib
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Build Status

Browser Support

A pure JavaScript Bitcoin library for node.js and browsers. Backed by (slowly improving) testing, proven by over a million wallet users. The backbone for almost all Bitcoin web wallets in production today.

Warning: Master is not stable. Expect the interface to change rapidly, including some of the examples below. This is not the original bitcoinjs-lib that was not updated for a while. The current bitcoinjs-lib has been refactored to clean things up, add new functionality and merge improvements from the community. If you are looking for the original, it will be tagged as 0.1.3. We will use 0.2.x for releases based on these changes, so be sure to use the 0.1.3 tag if you need the original version.


  • Bitcoin Testnet and Mainnet (production) support
  • HD Wallets
  • Highly secure random private key / address generation using window.crypto.getRandomValues
  • ECDSA signing and verification
  • Transaction creation (pay-to-pubkey-hash), support for multisignature transactions
  • A (somewhat incomplete) wallet implementation, improvements ongoing


npm install bitcoinjs-lib

Note: The npm version is currently out of date, are working to resolve this. The best way to use the latest code is to clone the repository.



var bitcoin = require('bitcoinjs-lib')

From the repo:

var bitcoin = require('./src/index.js')


Compile bitcoinjs-min.js with the following command:

$ npm run-script compile

After loading this file in your browser, you will be able to use the global Bitcoin object.


These examples assume you are running bitcoinjs-lib in the browser.

Generating a Bitcoin address

key = new Bitcoin.ECKey()

// Print your private key (a hex string)
// => 8c112cf628362ecf4d482f68af2dbb50c8a2cb90d226215de925417aa9336a48

// Print your public key (defaults to a Bitcoin address)
// => 14bZ7YWde4KdRb5YN7GYkToz3EHVCvRxkF

Creating a Transaction

tx = new Bitcoin.Transaction()

// Add the input (who is paying) of the form [previous transaction hash, index of the output to use]
tx.addInput("aa94ab02c182214f090e99a0d57021caffd0f195a81c24602b1028b130b63e31", 0)

// Add the output (who to pay to) of the form [payee's address, amount in satoshis]
tx.addOutput("1Gokm82v6DmtwKEB8AiVhm82hyFSsEvBDK", 15000)

// Initialize a private key using hex
key = new Bitcoin.ECKey("8c112cf628362ecf4d482f68af2dbb50c8a2cb90d226215de925417aa9336a48")

// Sign the first input with the new key
tx.sign(0, key)

// Print transaction serialized as hex
// => 0100000001313eb630b128102b60241ca895f1d0ffca2170d5a0990e094f2182c102ab94aa000000008a47304402200169f1f844936dc60df54e812345f5dd3e6681fea52e33c25154ad9cc23a330402204381ed8e73d74a95b15f312f33d5a0072c7a12dd6c3294df6e8efbe4aff27426014104e75628573696aed32d7656fb35e9c71ea08eb6492837e13d2662b9a36821d0fff992692fd14d74fdec20fae29128ba12653249cbeef521fc5eba84dde0689f27ffffffff01983a0000000000001976a914ad618cf4333b3b248f9744e8e81db2964d0ae39788ac00000000

// You could now push the transaction onto the Bitcoin network manually (see

Projects utilizing bitcoinjs-lib

Feel free to send pull requests to have your project/startup listed here.



  1. Fork the repo
  2. Push changes to your fork
  3. Create a pull request

Running the test suite

$ npm test



This library is free and open-source software released under the MIT license.

BitcoinJS (c) 2011-2012 Stefan Thomas Released under MIT license

JSBN (c) 2003-2005 Tom Wu Released under BSD license

CryptoJS (c) 2009–2012 by Jeff Mott Released under New BSD license

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