Overview
This tutorial demonstrates how to use the Biconomy Smart Account to perform a transaction with ERC-20 token payment. The provided code includes creating a Biconomy Smart Account, encoding a function call, building a transaction, and sending it with ERC-20 token payment.
Prerequisites
- Node.js installed on your machine
- A Biconomy API key and Bundler url, get from dashboard
For this tutorial we are going to mint and NFT on Amoy, this means we can use the following:
- bundlerUrl -->
https://bundler.biconomy.io/api/v2/80002/nJPK7B3ru.dd7f7861-190d-41bd-af80-6877f74b8f44 - preferred ERC20 token for gas payment --> 0xf555F8d9Cf90f9d95D34488e6C852796D9acBd31 (USDC)
- nft address --> 0x1758f42Af7026fBbB559Dc60EcE0De3ef81f665e
Step 1: Create Biconomy Smart Account and Encode Function Call
const smartWallet = await createSmartAccountClient({ signer, // can be viem client or ethers signer bundlerUrl, biconomyPaymasterApiKey,}); const encodedCall = encodeFunctionData({ abi: parseAbi(["function safeMint(address _to)"]), functionName: "safeMint", args: [recipient],});Create a Biconomy Smart Account instance and encode the function call for the transaction.
Step 2: Build the Transaction
const nftAddress = "0x1758f42Af7026fBbB559Dc60EcE0De3ef81f665e";const transaction = { to: nftAddress, data: encodedCall,};Build the transaction with the encoded function call.
Step 3: Send Transaction with ERC-20 Preferred Token Payment
const { wait } = await smartWallet.sendTransaction(transaction, { paymasterServiceData: { mode: PaymasterMode.ERC20, preferredToken: "0xf555F8d9Cf90f9d95D34488e6C852796D9acBd31", },}); const { receipt: { transactionHash }, userOpHash, success,} = await wait(); if (success == "true") { console.log("UserOp receipt", receipt); console.log("Transaction receipt", receipt.receipt);}You can choose from a list of ERC20 tokens to pay for the gas, not giving a preferred token will allow you to select from current supported tokens.
const feeQuotesResponse = await smartWallet.getTokenFees(transaction, { paymasterServiceData: { mode: PaymasterMode.ERC20 },}); const userSelectedFeeQuote = feeQuotesResponse.feeQuotes?.[0]; // Allow user to pick desired token const { wait } = await smartWallet.sendTransaction(transaction, { paymasterServiceData: { mode: PaymasterMode.ERC20, feeQuote: userSelectedFeeQuote, spender: feeQuotesResponse.tokenPaymasterAddress, maxApproval: true, },}); const { receipt: { transactionHash }, userOpHash, success,} = await wait(); if (success == "true") { console.log("UserOp receipt", receipt); console.log("Transaction receipt", receipt.receipt);}Send the transaction using the Biconomy Smart Account, specifying ERC-20 token payment details. Wait for the transaction to be mined and get the transaction hash.
That's it! You've successfully performed a transaction with ERC-20 token payment using the Biconomy Smart Account. Feel free to customize this example based on your specific use case.
