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Privy lets users create wallets through email or social login. This guide shows you how to connect Privy wallets to Biconomy using the AbstractJS SDK for gasless, cross-chain transactions.

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What We’re Building

By the end of this tutorial, your users will be able to:
  1. Log in with email (no seed phrase)
  2. Execute transactions without holding ETH for gas
  3. Perform cross-chain operations with one signature
How it works: When a user logs in with Privy, they get an embedded wallet. We upgrade this wallet to a smart account using EIP-7702, then route transactions through Biconomy’s MEE to handle gas payments.

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Step 1: Install Dependencies

npm install @privy-io/react-auth @biconomy/abstractjs viem
What these packages do:
  • @privy-io/react-auth — Privy’s React SDK for wallet creation and auth
  • @biconomy/abstractjs — Biconomy’s SDK for smart accounts and MEE
  • viem — Ethereum library for building transactions

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Step 2: Configure Privy Provider

Wrap your app with Privy’s provider. The key settings are: 
import { PrivyProvider } from "@privy-io/react-auth";

function App({ children }) {
  return (
    <PrivyProvider
      appId={process.env.NEXT_PUBLIC_PRIVY_APP_ID}
      config={{
        // Allow email login
        loginMethods: ["email"],
        
        embeddedWallets: {
          // Auto-create wallet on first login
          createOnLogin: true,
          // Don't prompt for every signature (better UX)
          noPromptOnSignature: true,
        },
      }}
    >
      {children}
    </PrivyProvider>
  );
}

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Step 3: Access the Embedded Wallet

After a user logs in, get their wallet from Privy: 
import { useWallets, useSignAuthorization } from "@privy-io/react-auth";
import { createWalletClient, custom } from "viem";
import { optimism } from "viem/chains";

function usePrivyWallet() {
  const { wallets } = useWallets();
  const { signAuthorization } = useSignAuthorization();
  
  // The embedded wallet is typically the first one
  const embeddedWallet = wallets?.[0];
  
  return { embeddedWallet, signAuthorization };
}

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Step 4: Create a Wallet Client

The wallet client is how you’ll sign transactions: 
async function getWalletClient(embeddedWallet) {
  // Switch to your target chain
  await embeddedWallet.switchChain(optimism.id);
  
  // Get the Ethereum provider from Privy
  const provider = await embeddedWallet.getEthereumProvider();
  
  // Create a viem wallet client
  const walletClient = createWalletClient({
    account: embeddedWallet.address,
    chain: optimism,
    transport: custom(provider),
  });
  
  return walletClient;
}

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Step 5: Sign EIP-7702 Authorization

This step upgrades the EOA to a smart account: 
// The Nexus smart account implementation address
const NEXUS_IMPLEMENTATION = "0x000000004F43C49e93C970E84001853a70923B03";

// Sign the authorization to upgrade the wallet
const authorization = await signAuthorization({
  contractAddress: NEXUS_IMPLEMENTATION,
  chainId: 0, // 0 = works on any chain
});
What just happened? The user signed a message that says “I authorize my wallet to behave like this smart contract.” Their address stays the same, but now it has smart account capabilities.

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Step 6: Create the Smart Account

Now create a Nexus account that can work across multiple chains: 
import { 
  toMultichainNexusAccount, 
  getMEEVersion, 
  MEEVersion 
} from "@biconomy/abstractjs";
import { optimism, base } from "viem/chains";
import { http } from "viem";

const nexusAccount = await toMultichainNexusAccount({
  chainConfigurations: [
    {
      chain: optimism,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0),
      // Use the original wallet address (EIP-7702 mode)
      accountAddress: embeddedWallet.address,
    },
    {
      chain: base,
      transport: http(),
      version: getMEEVersion(MEEVersion.V2_1_0),
      accountAddress: embeddedWallet.address,
    },
  ],
  signer: walletClient.account,
});

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Step 7: Create the MEE Client

The MEE client handles transaction execution: 
import { createMeeClient } from "@biconomy/abstractjs";

const meeClient = await createMeeClient({ 
  account: nexusAccount 
});

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Step 8: Execute a Gasless Transaction

Now you can execute transactions where gas is paid in any token: 
import { erc20Abi } from "viem";

const USDC_ADDRESS = "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85"; // USDC on Optimism

const { hash } = await meeClient.execute({
  // Required for EIP-7702 flow
  authorization,
  delegate: true,
  
  // Pay gas fees with USDC instead of ETH
  feeToken: {
    address: USDC_ADDRESS,
    chainId: optimism.id,
  },
  
  // Your transaction instructions
  instructions: [
    {
      chainId: optimism.id,
      calls: [
        {
          to: "0xRecipientAddress",
          value: 0n,
          data: "0x", // or encoded function data
        },
      ],
    },
  ],
});

// Wait for confirmation
const receipt = await meeClient.waitForSupertransactionReceipt({ hash });
console.log("Transaction complete:", receipt.hash);

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Complete Example

Here’s a full React component putting it all together: 
import { useState } from "react";
import { useWallets, useSignAuthorization } from "@privy-io/react-auth";
import { createWalletClient, custom, http, erc20Abi } from "viem";
import { optimism, base } from "viem/chains";
import {
  createMeeClient,
  toMultichainNexusAccount,
  getMEEVersion,
  MEEVersion,
} from "@biconomy/abstractjs";

const NEXUS_IMPLEMENTATION = "0x000000004F43C49e93C970E84001853a70923B03";
const USDC_OPTIMISM = "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85";

export function GaslessTransfer() {
  const { wallets } = useWallets();
  const { signAuthorization } = useSignAuthorization();
  const [status, setStatus] = useState("");

  async function sendGaslessTransaction() {
    try {
      setStatus("Setting up...");
      
      const embeddedWallet = wallets?.[0];
      if (!embeddedWallet) throw new Error("Please log in first");

      // Create wallet client
      await embeddedWallet.switchChain(optimism.id);
      const provider = await embeddedWallet.getEthereumProvider();
      const walletClient = createWalletClient({
        account: embeddedWallet.address,
        chain: optimism,
        transport: custom(provider),
      });

      setStatus("Signing authorization...");
      
      // Sign EIP-7702 authorization
      const authorization = await signAuthorization({
        contractAddress: NEXUS_IMPLEMENTATION,
        chainId: 0,
      });

      setStatus("Creating smart account...");
      
      // Create multichain account
      const nexusAccount = await toMultichainNexusAccount({
        chainConfigurations: [
          {
            chain: optimism,
            transport: http(),
            version: getMEEVersion(MEEVersion.V2_1_0),
            accountAddress: embeddedWallet.address,
          },
        ],
        signer: walletClient.account,
      });

      // Create MEE client
      const meeClient = await createMeeClient({ account: nexusAccount });

      setStatus("Executing transaction...");
      
      // Execute gasless transaction
      const { hash } = await meeClient.execute({
        authorization,
        delegate: true,
        feeToken: {
          address: USDC_OPTIMISM,
          chainId: optimism.id,
        },
        instructions: [
          {
            chainId: optimism.id,
            calls: [
              {
                to: "0x0000000000000000000000000000000000000000",
                value: 0n,
              },
            ],
          },
        ],
      });

      const receipt = await meeClient.waitForSupertransactionReceipt({ hash });
      setStatus(`Success! Hash: ${receipt.hash}`);
      
    } catch (error) {
      setStatus(`Error: ${error.message}`);
    }
  }

  return (
    <div>
      <button onClick={sendGaslessTransaction}>
        Send Gasless Transaction
      </button>
      <p>{status}</p>
    </div>
  );
}

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Key Takeaways

  1. Privy creates the wallet — Users log in with email, Privy creates an embedded wallet
  2. EIP-7702 adds smart features — The wallet gets upgraded without changing address
  3. MEE handles gas — Transactions are executed with any ERC-20 token for gas
  4. Cross-chain ready — Add more chains to chainConfigurations for multi-chain ops

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Next Steps