A module to store and interact with blocks

Usage no npm install needed!

<script type="module">
  import ethereumjsBlockchain from '';



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A module to store and interact with blocks.


npm install ethereumjs-blockchain




The following is an example to iterate through an existing Geth DB (needs level to be installed separately).

This module performs write operations. Making a backup of your data before trying it is recommended. Otherwise, you can end up with a compromised DB state.

const level = require('level')
const Blockchain = require('ethereumjs-blockchain').default
const utils = require('ethereumjs-util')

const gethDbPath = './chaindata' // Add your own path here. It will get modified, see remarks.
const db = level(gethDbPath)

new Blockchain({ db: db }).iterator(
  (block, reorg, cb) => {
    const blockNumber = utils.bufferToInt(block.header.number)
    const blockHash = block.hash().toString('hex')
    console.log(`BLOCK ${blockNumber}: ${blockHash}`)
  err => console.log(err || 'Done.'),

WARNING: Since ethereumjs-blockchain is also doing write operations on the DB for safety reasons only run this on a copy of your database, otherwise this might lead to a compromised DB state.


See our organizational documentation for an introduction to EthereumJS as well as information on current standards and best practices.

If you want to join for work or do improvements on the libraries have a look at our contribution guidelines.