If you’re thinking about creating a Web3 product, you came to the right place. Here’s how to create your first blockchain application with Ethereum, Web3.js, and Solidity smart contracts. You don’t have to know anything about blockchain to follow along.

First of all the basics: What is a blockchain? A blockchain is a peer-to-peer network of nodes that all talk to one another. These nodes are essentially computers that share responsibilities similar to web servers, like running programs and storing data that can be accessed whenever you’re connected to the blockchain. All the nodes work together to create a public network that anyone can connect to.

However, blockchains work differently from traditional web servers. All of the code and data on the blockchain is decentralized, i.e., it’s distributed across all the nodes in th network. It does not lie on a central web server.

All of this data is contained in bundles of records called blocks which are chained together to make up the public ledger. All of the nodes on the network participate in ensuring that this data remains secure an unchanged.

What Is A Smart Contract?

Smart contracts the building blocks we use to create blockchain applications. They are programs that we can write with source code and deploy to the blockchain.

Smart contracts are immutable, which means that once they’ve been created they cannot change! Once a smart contract is deployed to a blockchain, its code cannot be updated like a normal application. That’s because it represents a digital contract or agreement. Any time someone buys an item in the marketplace, they’ll send Ethereum cryptocurrency to the smart contract. 

Let’s move to building a Blockchain App?

Installing Dependencies

First, you’ll need to set up a person blockchain to develop the application locally.

The dependency is a personal blockchain, which is a local development blockchain that can be used to mimic the behavior of a public blockchain. 

After you have a private blockchain running, you need to configure your environment for developing smart contracts. The first dependency you’ll need is Node Package Manager, or NPM, which comes with Node.js. You can see if you have node already installed by going to your terminal and typing:

$ node -v

If you don’t have node already installed you can visit the Node.js website to download it.

Part 1: Project Setup

First, make sure you installed all of your dependencies from the previous section.

Part 2: Sell Products

Next, you’ll be building out the marketplace smart contract. We’ll create the first feature, which will allow a user to list an item for sale in the marketplace. 

Part 3: Buy Products

Now let’s create a function to purchase products. Whenever someone calls this function, they will submit the id of the product that they want to purchase (this will be handled by our client side application).

Part 4: Marketplace Website Setup (Front End)

Now let’s start building the client side application for the Marketplace. Here’s what we’ll do in this section:

  • Start the app, and run the starter kit in our browser
  • Connect our web browser to the blockchain
  • Connect our web app to the blockchain, and start talking to the Marketplace smart contract

Part 5: Sell Products (Front End)

Now let’s create a way to sell products from our marketplace website. We’ll do these tasks:

  • Create a react component that holds the scaffold for our code, including a form that allows users to list new products, and a table that shows products for sale.
  • We’ll wire up the form so that users can actually list their product for sale on the blockchain.