Visa Experimental Solution Overview: Paying On-Chain Gas Fees with Visa Cards

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Introduction

The blockchain industry faces a significant challenge in simplifying crypto payments for mainstream users. Visa has pioneered an experimental solution that enables users to pay on-chain gas fees directly with Visa cards using fiat currencies, streamlining blockchain transactions while enhancing accessibility.

Core Innovation:
This approach leverages Ethereum's ERC-4337 standard and a "Paymaster" smart contract, eliminating the need for users to hold native tokens (e.g., ETH) solely for gas fees.


The Problem: Complexity in Blockchain Transactions

Key Pain Points:

  1. Gas Fee Complexity

    • Every blockchain operation requires gas fees payable in native tokens (e.g., ETH on Ethereum), even for stablecoin transactions.
    • Users must maintain separate token balances or resort to convoluted acquisition methods (e.g., exchanges, bridges).
  2. Friction in Token Acquisition

    • Centralized exchanges or on-ramp services add steps, delays, and exposure to price volatility.
    • Technical barriers deter non-crypto-native users.
  3. Example Scenario:
    A user like "Alex" must estimate ETH needs for DeFi transactions, often overpaying or underpaying due to gas fee fluctuations.

The Solution: Visa’s Paymaster Framework

How It Works:

  1. Paymaster Smart Contract

    • Acts as a gas fee intermediary, accepting fiat payments via Visa cards and covering chain fees on behalf of users.
    • Integrates with ERC-4337’s account abstraction for seamless UX.
  2. User Flow:

    • Wallet generates a "User Operation" request.
    • Visa’s Paymaster web service calculates fees in fiat, processes card payments, and returns a digital signature.
    • Signature validates the transaction on-chain without native token holdings.
  3. Technical Components:

    • Chain Offloading: Delegates checks to off-chain services for efficiency.
    • Signature Verification: Uses public-key cryptography to ensure payment authenticity (see code snippet below).
// Example: Paymaster signature verification (Ethereum Goerli testnet)
function validatePaymasterUserOp(
    UserOperation calldata op,
    bytes32 requestId,
    uint256 maxCost
) external view returns (bytes memory context) {
    require(signatureIsValid(op.signature), "Invalid signature");
    // Proceed if validation passes
}

Experimental Implementation

Key Steps:

  1. Hackathon Prototype:

    • Visa’s internal teams built a proof-of-concept using Stackup’s userop.js and Ethereum’s Goerli testnet.
    • Successfully processed gas fees via card payments.
  2. Workflow:
    Simplified Paymaster Interaction

    • Step 1: User initiates transaction via wallet.
    • Step 2: Paymaster service authorizes card payment (using CyberSource APIs).
    • Step 3: Digital signature generated and returned.
    • Step 4: User operation executed on-chain.

Benefits and Future Applications

Advantages:

👉 Explore Visa’s Crypto Solutions

Potential Use Cases:


FAQs

1. Can I use any Visa card for gas fee payments?

Yes, the solution supports most Visa debit/credit cards linked to fiat accounts.

2. Is this available on all blockchains?

Currently experimental on Ethereum (Goerli testnet), with potential expansion to other EVM chains.

3. How are gas fees calculated in fiat?

Rates are pegged to real-time ETH prices and adjusted for network conditions.

4. Does Visa store my crypto wallet details?

No. Wallet interactions remain self-custodied; Visa only processes the fiat payment.

5. When will this launch publicly?

No official timeline yet—stay updated via 👉 Visa Crypto Solutions.


Conclusion

Visa’s Paymaster experiment demonstrates how traditional finance infrastructure can bridge the gap to Web3, making blockchain transactions as intuitive as card payments. By abstracting gas fee complexities, this innovation could accelerate crypto adoption while maintaining security and decentralization principles.

For further reading, visit Visa’s official crypto solutions page.