How to Fork Ethereum Blockchain with Ganache.

April 12, 2022

Overview

Forking and running a local simulated Ethereum environment is essential if you want to work with DeFi or do Ethereum development in general. In this guide, we’ll cover how to fork Ethereum Blockchain with Ganache

What is Ganache?

Ganache is an Ethereum developer tool that allows you to simulate a blockchain environment locally and test deployed smart contracts. You can use Ganache across the entire development cycle; enabling you to develop, deploy, and test your dApps in a safe and deterministic environment. 

Smart contracts, once deployed on a blockchain, cannot be changed, so it becomes critical to thoroughly test and debug smart contracts before deploying them on the blockchain. Therefore it is essential to have a local blockchain environment that can free the developers from transaction costs and delays. Ganache is specifically designed for this. It is a local in-memory blockchain for development and testing purposes that simulate the real Ethereum network with some accounts funded with test Ether. 

Why Fork Ethereum blockchain?

A fork in software development means making a copy of something separate from the original thing. Forking the Ethereum blockchain means copying the Ethereum blockchain’s state at a certain block and making a copy of it to make your changes moving forward. This allows working with the Ethereum network without altering the actual Ethereum mainnet. The primary reason to do this is to work with existing smart contracts on the blockchain without recreating them. For example, if you want to work with a particular DeFi protocol, you can find that protocol’s smart contract and fork the network for that block. This will allow you to test your project with the smart contract without making real transactions.

Booting our Ethereum node

We could use pretty much any Ethereum client, such as Geth or OpenEthereum (fka Parity for our purposes today. Since that is a bit too involved for forking a block, we'll just grab a free endpoint from QuickNode to make this easy. We’ll need a mainnet endpoint to get data from the chain as we are trying to make a simulated mainnet locally. After you've created your free ethereum endpoint, copy your HTTP Provider endpoint:

 
Screenshot of Quicknode Ethereum endpoint
 

You'll need this later, so copy it and save it.

Installing Ganache CLI

We’ll use Ganache CLI to fork the Mainnet; Ganache CLI uses ethereumjs to simulate full client behavior making development on Ethereum faster, easier, and safer. 

You can download Ganache CLI using npm (Node Package Manager),

installing ganache cli

Copy
$ npm install -g ganache-cli

Or yarn package manager.

installing ganache cli

Copy
$ yarn global add ganache-cli

The most common issue at this step is an internal failure with `node-gyp`. You can follow node-gyp installation instructions here.

Note: You will need to have your python version match one of the compatible versions listed in the instructions above if you encounter the node-gyp issue. 

Another common issue is a stale cache; clear your npm cache by simply typing the below into your terminal:

installing ganache cli

Copy
$ npm cache clean

If everything goes right, Ganache CLI will be installed on your system.

Fork Ethereum Mainnet using Ganache

To fork the mainnet, open your terminal/cmd and copy-paste the following:

fork ethereum mainnet using ganache

Copy
$ ganache-cli --fork <ADD_YOUR_QUICKNODE_URL_HERE>

Replace ADD_YOUR_QUICKNODE_URL_HERE with the QuickNode HTTP URL we got earlier and run the command; you must see something similar to this.


It will fork the mainnet at the blockchain’s latest block, 12200647, in the above example. You can query the forked chain by pinging localhost:8545.

You can fork at a specific block in the blockchain by mentioning the block number along with ‘@’ after your node URL.

fork ethereum mainnet using ganache

Copy
$ ganache-cli --fork <ADD_YOUR_QUICKNODE_URL_HERE>@<block_number>

Let’s say we want to do some development on the xDai chain which resides on the Ethereum blockchain network and uses xDai for gas. We can search for Dai on etherscan, and by going to the holder’s section, we can view the biggest Dai holders copy an address and run the following. 

fork ethereum mainnet using ganache

Copy
$ ganache-cli --fork <ADD_YOUR_QUICKNODE_URL_HERE> -u <address of token holder>

Here ganache will fork the Ethereum blockchain and unlock (-u) the above account for the local ganache environment. Using ganache-cli we can impersonate a particular account address which is usually locked for use. We can also make transactions on the simulated blockchain from that account address.

Note: The tokens you get to use are not real tokens and are meant to be used for development and testing purposes.

Note: You’ll need a node with an archive add-on to access the blocks older than 64 blocks from the latest block.

Querying the forked chain

Now, let’s get some information from the forked chain; we’ll make an eth_getBlockByNumber call that will return information about the block at which we forked the chain. We’ll need to convert the block number from decimal to hexadecimal and add a 0x prefix. 

querying the forked chain

Copy
$ curl --data '{"method":"eth_getBlockByNumber","params":["0xBA29D2",false],"id":1,"jsonrpc":"2.0"}' -H "Content-Type: application/json" -X POST localhost:8545

We’ll get an output something like this.


The above output has data about the block like the transactions, gas used in the block, timestamp, miner’s address, etc. Here’s the complete output.

Conclusion

Now that you have a local blockchain environment yourself, you can interact with the deployed contracts and build something extraordinary. Refer to Ganache CLI Readme for more Ganache features.

Subscribe to our newsletter for more articles and guides on Ethereum. If you have any feedback, feel free to reach out to us via Twitter. You can always chat with us on our Discord community server, featuring some of the coolest developers you’ll ever meet :)

Related articles 53

How to Send a Transaction On Solana Using JavaScript
Apr 13, 2022

Hello reader! Today is an exhilarating day because we are going on an expedition to the Solana Blockchain. Solana is an up-and-coming blockchain seeking to improve upon the current ecosystem's solutions to the complex problem of providing a secure, scalable, decentralized...

Continue reading
How to do a non-custodial transaction with QuickNode
Apr 12, 2022

Private keys are one of the most sensitive pieces of data when it comes to cryptography and the blockchain. However, there has always been debate/confusion about choosing between custodial wallets (where the wallet provider has custody of the user’s private key) and...

Continue reading
How to connect to Ethereum using .NET (Nethereum)
Apr 12, 2022

Dotnet or .NET is very popular for the development of desktop applications, most Windows desktop applications are built using .NET, and it also contributes largely to web application’s tech stack. In this guide, let’s see how we can connect to Ethereum using .NET and

Continue reading
How to Set Up a Near Project from Scratch
Jan 27, 2022

In this tutorial we will look at how we can setup a basic NEAR project from scratch, installing and configuring dependencies and customizing the project to work well with AssemblyScript.We will first start by initializing our project with a package.json file using...

Continue reading
Como crear y lanzar un ERC-721 (NFT)
Dec 29, 2021

Coleccionables digitales que son compatibles con ERC-721 se han vuelto muy populares desde el lanzamiento de Cryptokitties y han ganado adopción masiva en los últimos meses. Esta guía cubrirá la parte de creación y lanzamiento...

Continue reading
How to connect to Ethereum network using Java / Web3j
Apr 12, 2022

We can say that Java is one of the most versatile languages out there, and it continues to be relevant in today's time. Java is so popular because of its massive user base and use cases. In this guide/tutorial, we'll learn how to connect to the Ethereum Blockchain network...

Continue reading
How to integrate IPFS with Ethereum
Apr 12, 2022

It can be costly to store massive files on a blockchain mainnet, and this is where decentralized file storing systems like IPFS can come in handy. Sometimes, NFTs use IPFS as well. In this guide, we’ll cover how we can integrate IPFS with...

Continue reading
How to Connect to the Ethereum Network using Ruby
Jun 13, 2022

The Ruby programming language has a huge fanbase. Ruby was developed by its creator with an intention to invent a language developers can enjoy learning and using. Ruby has been largely accepted by developers all around the world since its launch, in fact, the biggest...

Continue reading
How to connect to Ethereum network with ethers.js
Apr 12, 2022

When someone thinks of developing a dApp the first tool that comes to their mind is web3.js which is pretty common because of its popularity in the community and wide use cases, dApp development has been consistently growing and there are a lot of developers who want to...

Continue reading
How to Mint an NFT on Solana
Apr 12, 2022

Updated at: April 10, 2022Welcome to another QuickNode guide on Solana - the up-and-coming blockchain that seeks to solve the scalability issues of Ethereum. We will be walking through step-by-step how to create an NFT on Solana. NFT, short for Non Fungible Token,...

Continue reading
The Web3 Developer Stack
Apr 12, 2022

A developer stack is a bag of technologies a developer possesses. For example, MEAN (MongoDB, Express.js, AngularJS/Angular, and Node.js) and MERN (MongoDB, Express.js, React, and Node.js) are common web developer stacks. Similarly, today we will learn more about the web3...

Continue reading
How to deploy a smart contract with Brownie
Apr 12, 2022

Python is one of the most versatile programming languages; from researchers running their test models to developers using it in heavy production environments, it has use cases in every possible technical field. In today's guide, we will learn about Brownie, a Python-based...

Continue reading
How to Get All Tokens Held by a Wallet in Solana
Jun 24, 2022

Hello readers! To kick off Solana Summer and the current whitelist meta, we thought it would be helpful to dig into all of the token accounts you and your users have using the getParsedProgramAccounts method. This tool is convenient for querying different...

Continue reading
Introduction to Scaffold-ETH 🏗
Dec 29, 2021

Developing applications involves juggling several moving pieces like front-ends, back-ends, and databases. But developing a decentralized application on a blockchain adds a few more elements like smart contracts and nodes that allow you to connect to the...

Continue reading
Como crear un NFT en SOLANA
Dec 29, 2021

¡Hola querido lector! Bienvenidos a una nueva guía de Solana.Solana es una blockchain que promete mucho a la hora de intentar resolver los problemas de escalabilidad que podemos apreciar en otras blockchains, como Ethereum por...

Continue reading
How to Send an EIP-1559 Transaction
Apr 12, 2022

While Ethereum has been trying to scale, it has encountered some gas price issues. Many layer 2 solutions and sidechains sprang into existence to solve this problem, but Ethereum is the main chain, and at some point, it has to be improved. EIP-1559 was introduced to...

Continue reading
How to Create an Address in Solana using JavaScript
Apr 12, 2022

Hello reader! Welcome to QuickNode's first Solana guide. Solana is an up-and-coming blockchain that seeks to solve the scalability issues that Ethereum has been handling. You will walk through step-by-step how to create a Solana address using the @solana/web3.js...

Continue reading
How to create your own DAO with Aragon
Apr 12, 2022

Blockchain provides us with the power of decentralization. Decentralization means the transfer of power to users/members rather than having a single centralized authority governing everything; it enables various use cases in finance, governance, voting, fundraising, etc....

Continue reading
How to Connect to Terra with JavaScript using Terra.js
Apr 12, 2022

Stablecoins have been bridging the gap between traditional currencies and blockchains. Stablecoins offer stable price tokens pegged by a reserve asset which is often a fiat current like USD, EUR, GBP. The Terra protocol provides a framework to work with stablecoins. This...

Continue reading
How to connect to Ethereum network using Go
Apr 12, 2022

Go helps you make faster scalable backends and this guide will show you how to connect your backend to Ethereum (and make it even faster, more reliable, and globally accessible, all thanks to QuickNode’s global infrastructure). What is...

Continue reading
How To Fork Ethereum Mainnet with Hardhat
Apr 12, 2022

Forking the chain at an older block of the blockchain is helpful if you want to simulate the blockchain’s state at that block; Hardhat has this functionality built in. In this guide, let’s go through the process of forking the Ethereum Mainnet at an older...

Continue reading
How to connect to Ethereum using PHP
Apr 12, 2022

PHP is a very popular choice among developers and has a vast community due to its long presence in web development. In this guide, we’ll cover how to connect to Ethereum with PHP using the web3.php...

Continue reading
How to use Subspace with QuickNode
Apr 12, 2022

In this guide, we'll understand a bit about reactive development and how to use Subspace with QuickNode.JavaScript is the programming language behind most of the internet apps and websites. JavaScript today has become one of the most used programming languages,...

Continue reading
How to Connect Your Dapp With MetaMask Using Ethers.js
Dec 29, 2021

In our dApp, we will have a simple react user interface that has a material button asking the user to connect to MetaMask. And if they do not have an account, they can create one or log in to their account. They will then view their wallet balance and address displayed on...

Continue reading
How to generate a new Ethereum address in Go
Dec 29, 2021

Golang is very popular among backend developers for building infrastructures and microservices. Go is a procedural programming language. Developed in 2007 by Robert Griesemer, Rob Pike, and Ken Thompson at Google, then launched in 2009 as...

Continue reading
How to generate a new Ethereum address in Python
Dec 29, 2021

Python is one of the most versatile programming languages out there with an abundance of use cases; We can build many applications with Python from client-side to back end. In this guide, we will cover creating an Ethereum address in Python using the

Continue reading
How to Lazy Mint an NFT on Rarible with Rarepress
Apr 12, 2022

NFTs are great for creators to monetize their artwork and for people to get ownership of an item. But since gas prices are usually high given the highly in-demand space on Ethereum, minting an NFT or an NFT collection can become costly for a creator. Lazy minting solves...

Continue reading