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How to Get Paid in USDC - The Easiest Way

#cryptocurrency #tutorial #web3

If you've ever tried to integrate cryptocurrency payments into your application, you know the pain. Between managing gas fees, handling multiple chains, dealing with custody concerns, and wrestling with complex wallet integrations, what seems like a simple "accept payment" feature can quickly turn into a multi-week engineering project.

In this post, I'll walk through the technical landscape of USDC payment acceptance and share an approach that eliminates most of the friction.

The Traditional Approach (and Why It's Hard)

Let's say you want to accept USDC payments on Ethereum or Solana. Here's what you'd typically need to handle:

1. Gas Fee Management

On EVM chains, every token transfer requires the sender to pay gas in the native token (ETH). This creates a terrible UX:

User: "I want to pay 100 USDC"
System: "Sure, but first you need 0.002 ETH for gas"
User: "I don't have ETH, I only have USDC"
System: "..."
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You either force users to hold native tokens, or you build a complex gas abstraction layer yourself.

2. Multi-chain Complexity

USDC exists on Ethereum, Polygon, Solana, Base, Arbitrum, and more. Each chain has different:

  • Contract addresses
  • Transaction formats
  • Confirmation times
  • RPC endpoints
  • Wallet connection methods

Supporting even 2-3 chains means maintaining parallel codepaths.

3. Custody Concerns

Most payment processors hold your funds temporarily. This introduces:

  • Counterparty risk
  • Compliance headaches
  • Withdrawal delays
  • Trust requirements

For many use cases, you just want funds to go directly to your wallet.

4. Webhook Reliability

Building reliable payment notifications means handling:

  • Retry logic
  • Signature verification
  • Idempotency
  • Chain reorgs

A Better Approach: Gasless, Non-Custodial Payments

The key insight is that modern stablecoins like USDC support meta-transactions via ERC-3009 (EVM) and similar patterns on Solana. This means:

Users can authorize transfers by signing a message, without paying gas themselves.

Here's how it works technically:

ERC-3009: Transfer With Authorization

USDC implements transferWithAuthorization, which allows gasless transfers:

function transferWithAuthorization(
    address from,
    address to,
    uint256 value,
    uint256 validAfter,
    uint256 validBefore,
    bytes32 nonce,
    bytes memory signature
) external;
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The flow:

  1. User signs an EIP-712 typed message authorizing the transfer
  2. A relayer (who pays gas) submits the transaction with the signature
  3. USDC contract verifies the signature and executes the transfer

The user never needs ETH. They just sign.

Building the Payment Flow

Here's a simplified version of what a gasless payment integration looks like:

// Frontend: Collect user signature
const domain = {
  name: 'USD Coin',
  version: '2',
  chainId: 8453, // Base
  verifyingContract: USDC_ADDRESS
};

const types = {
  TransferWithAuthorization: [
    { name: 'from', type: 'address' },
    { name: 'to', type: 'address' },
    { name: 'value', type: 'uint256' },
    { name: 'validAfter', type: 'uint256' },
    { name: 'validBefore', type: 'uint256' },
    { name: 'nonce', type: 'bytes32' }
  ]
};

const message = {
  from: userAddress,
  to: merchantAddress,
  value: parseUnits('10', 6), // 10 USDC
  validAfter: 0,
  validBefore: Math.floor(Date.now() / 1000) + 3600,
  nonce: randomBytes32()
};

const signature = await wallet.signTypedData(domain, types, message);
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// Backend: Submit to relayer for settlement
const response = await fetch('https://relayer.example.com/settle', {
  method: 'POST',
  body: JSON.stringify({
    network: 'base',
    payload: {
      signature,
      authorization: message
    }
  })
});

const { txHash } = await response.json();
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The relayer handles gas, the user just signs, and funds go directly to the merchant address.

Practical Implementation

If you want to skip building all this infrastructure yourself, there are services that handle the relayer, multi-chain support, and notification systems out of the box.

One option I've been exploring is Payin Go, which provides:

Payment Links (No-code)

# Create a payment link via API
curl -X POST https://go.payin.com/api/v1/link/create \
  -H "Content-Type: application/json" \
  -d '{
    "recipientAddress": "0xYourWallet...",
    "name": "My Store"
  }'

# Response
{
  "linkId": "abc123",
  "payUrl": "https://go.payin.com/link/abc123"
}
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Share the link. Payers choose their chain, enter amount, sign, done. No gas needed.

API Integration (Programmatic)

// Create a checkout session
const checkout = await fetch('https://go.payin.com/api/v1/checkout/create', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    amount: '25.00',
    currency: 'USDC',
    network: 'base-sepolia',
    recipientAddress: '0xYourWallet...',
    callbackUrl: 'https://yoursite.com/webhook',
    callbackSecret: 'your-webhook-secret'
  })
});

const { paymentId, paymentUrl, expiresAt } = await checkout.json();

// Redirect user to paymentUrl
// They pay, you get a webhook
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The key properties:

Feature Benefit
Non-custodial Funds go directly to your wallet
Gasless Users pay with USDC only, no ETH/SOL needed
Multi-chain Base, Solana, Polygon, etc. from one integration
No registration Start accepting payments in seconds

Handling Webhooks

When a payment completes, you'll want to verify the webhook:

import { createHmac } from 'crypto';

function verifyWebhook(payload: string, signature: string, secret: string) {
  const expected = createHmac('sha256', secret)
    .update(payload)
    .digest('hex');

  return signature === `sha256=${expected}`;
}

// In your webhook handler
app.post('/webhook', (req, res) => {
  const signature = req.headers['x-payingo-signature'];

  if (!verifyWebhook(req.rawBody, signature, WEBHOOK_SECRET)) {
    return res.status(401).send('Invalid signature');
  }

  const { paymentId, status, txHash, amount } = req.body;

  if (status === 'PAID') {
    // Fulfill the order
    await fulfillOrder(paymentId);
  }

  res.status(200).send('OK');
});
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Real-world Use Cases

This pattern works well for:

E-commerce
Fixed-price checkout with webhook confirmation. Customer pays, you ship.

SaaS Subscriptions
Generate payment links per customer, track via webhooks, activate accounts programmatically.

Donations / Tips
Create a permanent link, share it everywhere, receive payments with optional email notifications.

Point of Sale
Real-time WebSocket notifications for in-person payments. Customer scans, pays, you hear a ding.

AI Agent Payments
HTTP 402 "Payment Required" responses for machine-to-machine micropayments. Your API can literally charge per request.

Solana Support

The same pattern works on Solana, but instead of EIP-712 signatures, you use partially-signed transactions:

// User signs a transaction where feePayer is left blank
const transaction = new Transaction().add(
  createTransferCheckedInstruction(
    userTokenAccount,
    USDC_MINT,
    merchantTokenAccount,
    userPublicKey,
    amount,
    6 // decimals
  )
);

// User signs their part
transaction.partialSign(userKeypair);

// Send to relayer, who adds feePayer signature and submits
const serialized = transaction.serialize({ requireAllSignatures: false });
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The relayer fills in the fee payer, signs, and broadcasts. User never needs SOL.

Wrapping Up

Accepting USDC doesn't have to be complicated. The combination of:

  1. Meta-transactions (ERC-3009) for gasless UX
  2. Non-custodial architecture for trust minimization
  3. Unified APIs across chains for simplicity

...makes it possible to add crypto payments to any application in an afternoon.

If you're building something and want to accept stablecoin payments without the infrastructure headache, check out Payin Go. It's free to use and you can create your first payment link in about 30 seconds.

Have questions about crypto payment integration? Drop a comment below or find me on Twitter.

Tags: #webdev #blockchain #payments #cryptocurrency #tutorial

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