Building a Local Full Node Blockchain Explorer from Scratch
As a developer, you’re no stranger to building tools and exploring blockchains. However, when it comes to using third-party blockchain explorers like Blockscout, Etherscan, or Infura, there’s often a limit on the number of requests per second (RPS) you can make before hitting your internet connection’s bandwidth caps. But what if you want more control over your own blockchain? Want to build a local full node explorer that allows you to query the blockchain without relying on external APIs?
The Case for an Open-Source Project
In this article, we’ll explore the benefits of building an open-source blockchain explorer from scratch and show you how to do it using a few simple steps.
Why Build Your Own Blockchain Explorer?
Building your own blockchain explorer offers several advantages:
- More control: By having full control over your codebase, you can ensure that everything works as expected without relying on third-party services.
- Scalability
: As the number of users increases, a local full node explorer allows for more simultaneous connections, potentially leading to faster performance and higher availability.
- Security: With direct access to the blockchain data, you can implement robust security measures, such as encryption and authentication, to protect your users’ data.
The Basics: Building a Local Full Node Explorer
To build a local full node explorer, we’ll use Python as our programming language. We’ll focus on creating a simple, lightweight implementation that uses only the Ethereum blockchain protocol.
import hashlib
import json
class Block:
def __init__(self, hash, index, previous_hash, timestamp, miner):
self.hash = hash
self.index = index
self.previous_hash = previous_hash
self.timestamp = timestamp
self.miner = miner
Step 1: Set up the Ethereum Node
First, we need to create a local Ethereum node using Web3.py. We’ll use the ethers
library to connect our blockchain.
from web3 import Web3
w3 = Web3(Web3.HTTPProvider('

Replace with your local Ethereum network
Step 2: Create a Block
Now that we have our node set up, let’s create a new block. We’ll use the createTransaction
method to generate a transaction and add it to the blockchain.
def create_block(data):
return w3.eth.getTransactionCount(w3.currentProvider)
Step 3: Sign the Block
Before we can send the block to the network, we need to sign it with our account private key. We’ll use the signTransaction
method to do this.
def sign_block(tx_data):
return w3.eth Account.sign_transaction([tx_data], w3.eth.getTransactionCount(w3.currentProvider)).signedTransaction
Step 4: Add the Block to the Blockchain
Now that we have our signed transaction, let’s add it to the blockchain using the add_block
method.
def add_block(block_data):
return w3.eth.sendrawtransaction(block_data)
Putting it all together
Here’s a simple example of how you can use these steps to build a local full node explorer:
“`python
import hashlib
import json
class Block:
def __init__(self, hash, index, previous_hash, timestamp, miner):
self.hash = hash
self.index = index
self.previous_hash = previous_hash
self.timestamp = timestamp
self.miner = miner
def create_block(data):
return w3.eth.getTransactionCount(w3.currentProvider)
def sign_block(tx_data):
return w3.eth.Account.sign_transaction([tx_data], w3.eth.getTransactionCount(w3.currentProvider)).signedTransaction
def add_block(block_data):
return w3.eth.