Gasless Transactions in React

In this tutorial, you will create a basic React app that lets you connect a wallet and send a gasless transaction with a smart account using the Owl Protocol ERC4337 (opens in a new tab) Account Abstraction API, Wagmi (opens in a new tab) hooks and a RainbowKit (opens in a new tab) wallet connector.

Clone The Repo

We have created the Owl Protocol tutorials-react repository (opens in a new tab) to get you started quickly.

git clone https://github.com/owlprotocol/tutorials-react.git owlprotocol-tutorials-react
cd owlprotocol-tutorials-react

Now, let's install the dependencies (we recommend using pnpm (opens in a new tab))

npm install

Then, copy the example environment variables. You do not need to change these.

cp .env.example .env

The main file we will be working with is App.tsx. Let's run vite to make sure everything is working

npm run dev

Initialize The Owl Provider

Initialize the Owl Provider in App.tsx to enable gasless transactions.

Note that this is already done for you in the starter repository.

This provider is used to interact with our API.

import { OwlProvider } from "@owlprotocol/ui-components";
 
import "./App.css";
 
export const App = () => {
    return (
        <>
            <h1>Owl React Tutorials</h1>
 
            <OwlProvider>
                {/* Add tutorial snippets below */}
            </OwlProvider>
        </>
    );
};

Create The Gasless Transaction Component

In this step, we will initialize wrappers to create blockchain interactions.

We will connect to the Hedwig Testnet chain, which has chain id 150150.

We start by fetching data about that chain by making a trpc call to the Owl API.

We then set up two providers:

RainbowKitProvider: adds UI components for users to pick a wallet and sign in
WagmiProvider: enables hooks for blockchain interactions such as sending transactions

Notice that in the config we pass to WagmiProvider, we initialize a list of connectors using connectorsForWallets. This is a wrapper function used to initialize a list of wallets to use and to display in the RainbowKit modal.

import { createConfig, WagmiProvider } from "wagmi";
import { type Chain, http } from "viem";
import { trpc } from "@owlprotocol/core-trpc/react-query";
import {
    connectorsForWallets,
    RainbowKitProvider,
    darkTheme,
} from "@rainbow-me/rainbowkit";
import { metaMaskWallet } from "@rainbow-me/rainbowkit/wallets";
 
import "@rainbow-me/rainbowkit/styles.css";
 
export const GaslessTransactionComponent = () => {
    // Get Hedwig Testnet chain data
    const [owlChain] = trpc.network.get.useSuspenseQuery({ chainId: 150150 });
    const chains = [owlChain] as readonly [Chain];
 
    const connectors = connectorsForWallets(
        [
            {
                groupName: "Recommended",
                wallets: [metaMaskWallet],
            },
        ],
        { projectId: "owlProtocol", appName: "Owl React Tutorials" }
    );
 
    const config = createConfig({
        chains,
        connectors,
        transports: { [owlChain.id]: http(owlChain.rpcUrls.default.http[0]) },
    });
 
    return (
        <WagmiProvider config={config}>
            <RainbowKitProvider theme={darkTheme()}>
                {/* We will be writing this component next */}
                <GaslessTransactionInnerComponent />
            </RainbowKitProvider>
        </WagmiProvider>
    );
};

Create The Gasless Transaction Inner Component

We now create the inner component, which consists of the RainbowKit button to connect a wallet, a button to send a transaction, and a button to disconnect all connectors. We also add the useOwlSimpleSmartAccount hook. This automatically overrides the wallet the users connects with to use a smart wallet.

Notice that when you send a transaction, the transaction hash will be displayed under. The data attribute of useSendTransaction gets populated once the transaction has successfully been sent.

import { useSendTransaction, useConnectors } from "wagmi";
import { zeroAddress } from "viem";
import { useOwlSimpleSmartAccount } from "@owlprotocol/ui-components";
import { ConnectButton } from "@rainbow-me/rainbowkit";
 
import "@rainbow-me/rainbowkit/styles.css";
 
const GaslessTransactionInnerComponent = () => {
    const { sendTransaction, data: txHash } = useSendTransaction();
    const currConnectors = useConnectors();
 
    useOwlSimpleSmartAccount();
 
    return (
        <>
            <ConnectButton />
 
            <button
                onClick={() =>
                    // A dummy transaction. Note that no ether is sent.
                    sendTransaction({
                        to: zeroAddress,
                        value: 0n,
                        data: "0x",
                    })
                }
            >
                Send Test Transaction
            </button>
 
            <p>{!!txHash && `Transaction Hash: ${txHash}`}</p>
 
            {/* Need to disconnect all connectors since we are connecting to two connectors: the main connector and the smart account connector */}
            <button
                onClick={() => currConnectors.forEach((c) => c.disconnect())}
            >
                Disconnect All
            </button>
 
            <br />
        </>
    );
};

Add The Gasless Transaction Component To The App

Back in App.tsx, import and add the GaslessTransactionComponent.

import { OwlProvider } from "@owlprotocol/ui-components";
import { GaslessTransactionComponent } from "./tutorials/gasless-transactions.jsx";
 
export const App = () => {
    return (
        <>
            <h1>Owl React Tutorials</h1>
 
            <OwlProvider>
                <GaslessTransactionComponent />
            </OwlProvider>
        </>
    );
};

And voilà! Run pnpm dev again if needed, and check out your first app with a gasless transaction. Make sure to connect a wallet, and then click on Send Test Transaction.

To see the final component, go to our GitHub (opens in a new tab)

Gasless Transactions Owl Wallet