Accept Payments From Humans

Choose the payment rail that matches your checkout. A direct USDC transfer works with any EIP-1193 wallet, and B20 adds issuer-defined policy controls and an onchain order memo.

Demo

Rail	Best for	Integration
Direct USDC	Wallet-agnostic ERC-20 checkout	viem
B20 with memo	Issuer tokens and onchain reconciliation	viem or Solidity

Direct USDC
B20 with memo

Accept a wallet-native USDC transfer

Base Sepolia USDC is 0x036CbD53842c5426634e7929541eC2318f3dCF7c; Base mainnet USDC is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.

Testnet deployments can be reset. Confirm eth_getCode returns contract bytecode at the configured USDC address and that your faucet issued the same asset before asking a user to sign.

TypeScript

export async function sendUsdc(merchant: Address) {
  const { account, publicClient, walletClient } = await browserClients();
  const simulation = await publicClient.simulateContract({
    account,
    address: USDC,
    abi: erc20Abi,
    functionName: "transfer",
    args: [merchant, parseUnits("5", 6)],
  });
  const hash = await walletClient.writeContract(simulation.request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  if (receipt.status !== "success") throw new Error("USDC transfer reverted");
  return hash;
}

The receipt succeeds and the standard USDC Transfer event records the merchant and amount.

Accept B20 with a memo

A direct wallet can call transferWithMemo. A checkout contract can instead pull an approved amount with transferFromWithMemo and reject duplicate order IDs.

export async function sendB20WithMemo(token: Address, merchant: Address) {
  const { account, publicClient, walletClient } = await browserClients();
  const memo = stringToHex("order-8842", { size: 32 });
  const simulation = await publicClient.simulateContract({
    account,
    address: token,
    abi: b20PaymentAbi,
    functionName: "transferWithMemo",
    args: [merchant, parseUnits("25", 6), memo],
  });
  const hash = await walletClient.writeContract(simulation.request);
  const receipt = await publicClient.waitForTransactionReceipt({ hash });
  const events = parseEventLogs({ abi: b20PaymentAbi, logs: receipt.logs, strict: true });
  if (events[0]?.eventName !== "Transfer" || events[1]?.eventName !== "Memo") {
    throw new Error("Expected adjacent Transfer and Memo events");
  }
  return hash;
}

function pay(bytes32 orderId, uint256 amount) external {
    if (paid[orderId]) revert OrderAlreadyPaid(orderId);
    paid[orderId] = true;
    bool transferred = token.transferFromWithMemo(msg.sender, merchant, amount, orderId);
    require(transferred, "B20 transfer failed");
}

If the Solidity checkout calls transferFromWithMemo, the payer must approve it and any TRANSFER_EXECUTOR_POLICY must authorize the checkout contract. The merchant must still verify the expected amount before fulfillment.

See the complete verified payment fixtures for client construction, ABIs, and runnable projects.

Verify before fulfillment

A successful wallet prompt is not a fulfillment signal. Verify the recipient, token, sender, amount, memo when present, and replay state on your backend.

Verify a payment

Validate settlement and claim each transaction hash exactly once.

Build on Base

Issue Stablecoins

Integrate DeFi

Issue RWA

Accept Payments

Private Transactions

Demo

Accept a wallet-native USDC transfer

Accept B20 with a memo

Verify before fulfillment

Verify a payment

See also

​Demo

​Accept a wallet-native USDC transfer

​Accept B20 with a memo

​Verify before fulfillment

Verify a payment

​See also

Demo

Accept a wallet-native USDC transfer

Accept B20 with a memo

Verify before fulfillment

See also