Send a gasless transaction
Overview
This tutorial demonstrates how to send a simple transaction using ethers.js/viem and the Biconomy Smart Account with the @biconomy/account
SDK. The provided code assumes you have a Biconomy Paymaster API key.
You can get your Biconomy Paymaster API key from the dashboard here.
Prerequisites
- Node.js installed on your machine
- Biconomy Paymaster API key
- A Bundler url if you don't want to use the testnet one (for Amoy you can use https://bundler.biconomy.io/api/v2/80002/nJPK7B3ru.dd7f7861-190d-41bd-af80-6877f74b8f44)
- An rpc url (for Amoy can use https://rpc-amoy.polygon.technology/)
- An address to send the transaction to (replace
0xaddress
)
Step 1: Generate the config and Create Biconomy Smart Account
- viem
- ethers
import { createWalletClient } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { polygonAmoy } from "viem/chains";
import { createSmartAccountClient, PaymasterMode } from "@biconomy/account";
// Your configuration with private key and Biconomy API key
const config = {
privateKey: "your-private-key",
biconomyPaymasterApiKey: "your-biconomy-api-key",
bundlerUrl: "", // <-- Read about this at https://docs.biconomy.io/dashboard#bundler-url
};
// Generate EOA from private key using ethers.js
const account = privateKeyToAccount("0x" + config.privateKey);
const client = createWalletClient({
account,
chain: polygonAmoy,
transport: http(),
});
// Create Biconomy Smart Account instance
const smartWallet = await createSmartAccountClient({
signer: client,
biconomyPaymasterApiKey: config.biconomyPaymasterApiKey,
bundlerUrl: config.bundlerUrl,
});
const saAddress = await smartWallet.getAccountAddress();
console.log("SA Address", saAddress);
import { ethers } from "ethers";
import { createSmartAccountClient } from "@biconomy/account";
// Your configuration with private key and Biconomy API key
const config = {
privateKey: "your-private-key",
biconomyPaymasterApiKey: "your-biconomy-api-key",
bundlerUrl: "", // <-- Read about this at https://docs.biconomy.io/dashboard#bundler-url
rpcUrl: "rpc-url",
};
// Generate EOA from private key using ethers.js
let provider = new ethers.providers.JsonRpcProvider(config.rpcUrl);
let signer = new ethers.Wallet(config.privateKey, provider);
// Create Biconomy Smart Account instance
const smartWallet = await createSmartAccountClient({
signer,
biconomyPaymasterApiKey: config.biconomyPaymasterApiKey,
bundlerUrl: config.bundlerUrl,
});
const saAddress = await smartWallet.getAccountAddress();
console.log("SA Address", saAddress);
Get your signer from either ethers.js or viem and create a Biconomy Smart Account instance.
Step 2: Generate Transaction Data
const toAddress = "0xaddress"; // Replace with the recipient's address
const transactionData = "0x123"; // Replace with the actual transaction data
// Build the transaction
const tx = {
to: toAddress,
data: transactionData,
};
Specify the recipient's address and transaction data to build the simple transaction.
Step 3: Send the Transaction and wait for the Transaction Hash
// Send the transaction and get the transaction hash
const userOpResponse = await smartWallet.sendTransaction(tx, {
paymasterServiceData: {mode: PaymasterMode.SPONSORED},
});
const { transactionHash } = await userOpResponse.waitForTxHash();
console.log("Transaction Hash", transactionHash);
const userOpReceipt = await userOpResponse.wait();
if(userOpReceipt.success == 'true') {
console.log("UserOp receipt", userOpReceipt)
console.log("Transaction receipt", userOpReceipt.receipt)
}
Send the transaction using the Biconomy Smart Account and get the transaction hash. The transaction will be built into a User Operation and then send to the Bundler.
That's it! You've successfully sent a simple transaction using ethers.js/viem and the Biconomy Smart Account. Feel free to customize this example based on your specific use case.