Web3-Onboard

This tutorial is a step-by-step guide on how to integrate a wallet such as Phantom into your dApp using the Web3-Onboard library. Web3-Onboard is an EVM wallet library that supports Phantom on Ethereum and Polygon.
We will be going through step by step how to go from zero to a fully integrated Web3-Onboard button. If you already have a dApp that you are trying to integrate Phantom in, you can use our project as reference. At the end of this guide, your adapter will look like this:
The Web3-Onboard modal that shows after a user presses "connect"
Prerequisites
Node version >=16.12.0
A text editor/IDE (such as VSCode)
Some Knowledge of React
Creating The App
We recommend using Vite to create new react applications.
To create a new React application using Vite, run the following command in your terminal:
yarn create vite
1.This will ask you for a project name. Provide it a name here. For purposes of this tutorial I used "Web3-onboard-Sandbox".
2.It will then ask you to select a framework. Select "React" here.
3.Next it will ask for a variant. Select "Typescript" here.
Now change directory into your project and run:
yarn install
And make sure your app runs by running the command:
yarn dev
Before moving forward, we're going to configure Vite to recognize the window.ethereum object. Since we are in Typescript if we try to use window.ethereum without first doing this step, we will get a type error and be unable to compile our project.
open the vite-env.d.ts file in the src directory.
It should look like this:
/// <reference types="vite/client" />
All you need to do is extend the Window interface. To do so modify the vite-env.d.ts file to look like so:
/// <reference types="vite/client" />
​
interface Window {
    ethereum: any;
}
Now whenever we reference window.ethereum, we will not encounter any type errors.
With your app running, we can now move onto the Web3-Onboard specific pieces.
Installing Web3-Onboard
To install the appropriate package, run the following:
yarn add @web3-onboard/react @web3-onboard/phantom
Now you can use the web3-onboard package in your project and integrate Phantom as a wallet in the modal.
Initializing Web3-Onboard
First we will need to import the packages into our project. At the top of the App.tsx file add these two lines:
import { init, useConnectWallet } from "@web3-onboard/react";
import phantomModule from "@web3-onboard/phantom";
Next, we will can initialize the modal by calling the init hook. You can add this code to the project between your imports and your App component.
const phantom = phantomModule();
​
init({
  wallets: [phantom],
  chains: [
    {
      id: "0x1",
      token: "ETH",
      label: "Ethereum Mainnet",
      rpcUrl:
        "https://eth-mainnet.g.alchemy.com/v2/YOUR_API_KEY_HERE",
    },
  ]
});
Here you can see that we call the init hook that we imported, and provide the phantomModule to an array of wallets. Here you can also specify which chains your dapp supports.
Each chain requires an id, token, label, and rpcUrl.  Phantom currently supports Polygon, Ethereum Mainnet, Goerli, and Mumbai.
You can add as many chains as you would like. There are many configuration options that Web3-Onboard provides you. To see a full list of the different options you can check out their documentation here. You can customize your theme, i18n options, app metadata, realtime app notifications, and more.
With this bit of configuration out of the way we only need to add the button that will call the modal to the forefront of the screen to connect our wallet.
Adding A Connect Wallet Button
In your App component, you will utilize the useConnectWallet hook that you imported earlier.
Add this to the first line inside your component:
  const [{ wallet, connecting }, connect, disconnect] = useConnectWallet();
This gives you the connect and disconnect functions that we will attach to our button, as well as the wallet and connecting keys in an object that allow us to track state of various wallets and connection statuses.
We now have everything we need to add the actual UI. You can place this block in place of the basic counter that comes in the Vite starter.
<button disabled={connecting} onClick={() => (wallet ? disconnect(wallet) : connect())}>
    {connecting ? 'connecting' : wallet ? 'disconnect' : 'connect'}
</button>
If you save your project you should now have working connect button that displays the Phantom wallet button. Clicking on it will establish a connection to the dapp.
Here's what it will look like:
The landing page of our application
The Web3-Onboard modal that shows after a user presses "connect"
Conclusion
Web3-Onboard provides quite a lot out of the gate with very little work on your end as a developer. We hope that you enjoyed this guide.
If you got lost along the way do not worry. You can find the source code here to double check your work.
Last modified 3mo ago