;
};
Use the deployed `SpendPermissionPaymentCollector` when a wallet approves repeated collection. Your scheduler still creates a fresh `PaymentInfo` and unique salt for every billing period because each protocol payment can be charged only once.
## Demo
The demo above is mock only. If you want to see onchain demos on Vibenet, head to [Base chain demos](https://chain.base.org/demos).
## Charge One Billing Period
The collector reconstructs a spend permission from `PaymentInfo`: the payer is the account, the collector is the spender, the token and allowance come from the payment, and `preApprovalExpiry` is the permission end. Encode the permission signature and optional MagicSpend withdrawal request as `collectorData`.
Use a durable billing key such as `subscriptionId:periodStart` before submitting the protocol charge.
```typescript TypeScript lines wrap expandable highlight={8-10,15,19-20,28} theme={null}
export async function chargeSubscriptionPeriod(args: {
paymentInfo: PaymentInfo;
collectorData: Hex;
billingKey: string;
amount: bigint;
store: BillingStore;
}) {
if (!(await args.store.reserveOnce(args.billingKey))) {
throw new Error("Billing period was already submitted");
}
const simulation = await publicClient.simulateContract({
account,
address: AUTH_CAPTURE_ESCROW,
abi: authCaptureEscrowAbi,
functionName: "charge",
args: [
args.paymentInfo,
args.amount,
SPEND_PERMISSION_PAYMENT_COLLECTOR,
args.collectorData,
0n,
zeroAddress,
],
});
const hash = await walletClient.writeContract(simulation.request);
const receipt = await publicClient.waitForTransactionReceipt({ hash, confirmations: 2 });
if (receipt.status !== "success") throw new Error("Scheduled charge reverted");
await args.store.complete(args.billingKey, hash);
return receipt;
}
```
A successful charge emits `PaymentCharged` and creates a protocol `refundableAmount` for that billing period.
Store the billing key, `paymentInfoHash`, charge transaction, amount, and spend-permission usage in one durable workflow.
The [Commerce Payments Protocol](https://github.com/base/commerce-payments) does not run a scheduler. Protect the operator key, serialize retries, and do not reuse a prior period's `PaymentInfo` or salt.
## See Also
Use the same charge lifecycle for a one-time checkout.
Reverse a charged billing period before refund expiry.