⛽️ Paying Gas with ERC20 Tokens on Biconomy MEE

Biconomy MEE enables developers to offer flexible, chain-agnostic gas payments using any ERC-20 token 🔗, even across chains. Unlike older systems, such as ERC-4337, MEE supports true cross-chain gas payments, letting users pay for transactions on one chain using tokens from another 🌐.

This unlocks powerful UX patterns:

• Users can pay gas without native tokens.
• Gas can be paid with thousands of tokens, even using lending position tokens (e.g. aUSDC), LP tokens (e.g. ), governance tokens, derivatives, and more.
• Integrate with DeFi-native flows where users already hold non-native tokens.

1. 🔐 EIP-7702 EOAs (Used With Embedded Wallets)

Smart-account logic is installed directly on the EOA. Just pass a feeToken when quoting.

Learn how to set up EIP-7702 on your EOA

const quote = await meeClient.getQuote({
  instructions: [{
    calls: [{ to: zeroAddress, value: 0n }],
    chainId: optimism.id
  }],
 
  // mandatory for 7702 orchestration
  delegate: true,  
  
  // user-signed or supplied manually
  authorization,      
  feeToken: {
    address: usdcAddresses[base.id],
 
    // pay gas on Base while executing on Optimism
    chainId: base.id  
  }
});

🧪 2. Fusion Mode (Used With External Wallets)

Learn how to set up Fusion Mode

Fusion uses a Trigger + Companion Account. Fusion mode is used when working with External Wallets such as MetaMask, Rabby, Trust, ... Fusion mode must be used with those wallets as they don't allow apps to install code on EOAs through EIP-7702.

The token that funds the trigger must also be the gas token.

const trigger: Trigger = {
  chainId: optimism.id,
  tokenAddress: usdcAddresses[base.id],
  amount: parseUnits('2', 6)
};
 
const sendOneUSDCInstruction: Instruction = {
  chainId: base.id,
  calls: [{
    to: usdcAddresses[base.id],
    data: encodeFunctionData({
      abi: erc20Abi,
      functionName: 'transfer',
      args: [eoa.address, parseUnits('1', 6)]
    })
  }]
};
 
const feeToken: FeeTokenInfo = {
  address: trigger.tokenAddress,
  chainId: trigger.chainId
};
 
const { quote } = await meeClient.getFusionQuote({
  trigger,
  instructions: [sendOneUSDCInstruction],
  feeToken
});

• ✅ If token supports ERC-2612 (ERC20Permit), trigger is gasless.
• ❌ If not, user must first send an approve() tx (gas is needed).
• 🔁 Fusion requires same token for trigger and gas payment.
• 🔒 Only one token per user signature is supported.

🧠 3. Native Smart Contract Accounts (SCAs)

Use MEE Nexus SCAs to execute on one chain and pay gas on another. This is a very flexible method, but does not work on EOA wallets.

const sendOneUSDCInstruction: Instruction = {
  chainId: base.id,
  calls: [{
    to: usdcAddresses[base.id],
    data: encodeFunctionData({
      abi: erc20Abi,
      functionName: 'transfer',
      args: [eoa.address, parseUnits('1', 6)]
    })
  }]
};
 
const payGasWithUsdcOnOptimism: FeeTokenInfo = {
  address: usdcAddresses[optimism.id],
  chainId: base.id
};
 
const quote = await meeClient.getQuote({
  instructions: [sendOneUSDCInstruction],
  feeToken: payGasWithUsdcOnOptimism
});

✅ Most flexible mode. Any supported ERC-20 token from any supported chain can be used to pay for gas.

❌ Requires EOA users to deposit manually to a smart account address. Creates onboarding friction.

🧾 Key Takeaways

• 🧠 Use any ERC-20—not just standard tokens, but LPs, lending receipts, governance tokens, and more.

• 🔄 Execute on one chain, pay on another.

• 🎛 Choose orchestration method based on wallet type:

  • EIP-7702: simplest
  • Fusion: requires trigger
  • SCAs: most advanced, composable

• 🔍 Fusion requires ERC20Permit for gasless usage.

• 💡 Consider gas sponsorship to remove all gas costs for users.

Check token compatibility, orchestration mode, and user wallet type to determine the best pattern for your app.