;
};
Choose the payment rail that matches your checkout. Base Pay gives Base Account users a one-tap USDC experience, 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 |
| ------------- | ---------------------------------------- | ------------------- |
| Base Pay | Consumer checkout and sponsored gas | `@base-org/account` |
| Direct USDC | Wallet-agnostic ERC-20 checkout | viem |
| B20 with memo | Issuer tokens and onchain reconciliation | viem or Solidity |
## Accept USDC with Base Pay
`pay()` opens the Base Account approval flow. Keep `testnet` consistent when checking the returned transaction hash.
```typescript TypeScript lines wrap expandable highlight={2,3} theme={null}
export async function acceptWithBasePay(merchant: Address) {
const payment = await pay({ amount: "5.00", to: merchant, testnet: true });
const result = await getPaymentStatus({ id: payment.id, testnet: true });
if (result.status !== "completed" || result.recipient?.toLowerCase() !== merchant.toLowerCase()) {
throw new Error(`Payment is not complete: ${result.status}`);
}
return payment.id;
}
```
The function returns a completed Base Sepolia transaction hash whose recipient is the merchant.
## 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 TypeScript lines wrap expandable highlight={3,10} theme={null}
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.
```typescript TypeScript lines wrap expandable highlight={4,8,11} theme={null}
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;
}
```
```solidity Solidity lines wrap expandable highlight={4} theme={null}
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](https://github.com/base/docs/tree/master/examples/verified-doc-samples) 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.
Validate settlement and claim each transaction hash exactly once.
## See also
* [Collect payer info](/build-on-base/accept-payments/collect-payer-info) · [Accept subscriptions](/build-on-base/accept-payments/accept-subscriptions)
* [`pay()`](/sdks/base-account/reference/base-pay/pay) and [B20 memos](/base-chain/specs/upgrades/beryl/b20#memos)