Metered API

import {
  Access,
  Billing,
  Offer,
  Purchase,
  checkAccess,
  correctMeteredUsage,
  createCheckout,
  enrollPostpaidSubscription,
  finalizeMeteredInvoice,
  getMeteredInvoiceCollection,
  processPaymentNotification,
  recordMeteredUsage,
  registerOffers,
} from "@byfungsi/sapa";

const apiAccess =
  yield *
  Access.entitlements({
    entitlements: ["api.use"],
    duration: "purchased_period",
  });
const apiPurchase =
  yield *
  Purchase.parse({
    key: "api.metered.access",
    revision: 1,
    provides: [apiAccess],
  });
const apiBilling =
  yield *
  Billing.meteredSubscription({
    family: "api",
    interval: "month",
    meter: { key: "api.request", revision: 1 },
    rate: { currency: "IDR", amount: 25n, perUnits: 10n, rounding: "trunc" },
    accessPolicy: { key: "api.postpaid_access", revision: 1 },
  });
const meteredApi =
  yield *
  Offer.parse({
    key: "api.metered",
    revision: 1,
    purchase: apiPurchase,
    billing: apiBilling,
  });

yield * registerOffers([meteredApi]);
const enrollment =
  yield *
  enrollPostpaidSubscription({
    idempotencyKey: "api-enrollment-42",
    externalCustomerId: "customer-42",
    offerKey: meteredApi.key,
    offerRevision: meteredApi.revision,
  });

yield *
  recordMeteredUsage({
    idempotencyKey: "request-batch-2026-09-42",
    subscriptionId: enrollment.subscriptionId,
    meter: { key: "api.request", revision: 1 },
    quantity: 120n,
    occurredAt: usageOccurredAt,
  });
yield *
  correctMeteredUsage({
    idempotencyKey: "request-correction-2026-09-42",
    originalUsageIdempotencyKey: "request-batch-2026-09-42",
    quantityDelta: -20n,
    correctedAt,
  });

const invoice =
  yield *
  finalizeMeteredInvoice({
    subscriptionId: enrollment.subscriptionId,
    periodEndsAt,
  });
if (invoice.collectionStatus === "payment_due") {
  yield *
    createCheckout({
      type: "invoice",
      invoiceId: invoice.invoiceId,
      provider: "midtrans",
      customer,
      successUrl,
      cancelUrl,
      clientIp: null,
      idempotencyKey: `invoice-${invoice.invoiceId}`,
    });
}

yield *
  processPaymentNotification({
    provider: "midtrans",
    payload: rawProviderPayload,
  });
const collection = yield * getMeteredInvoiceCollection(invoice.invoiceId);
const granted =
  yield *
  checkAccess({ externalCustomerId: "customer-42", entitlement: "api.use" });

Install meter api.request@1 and access policy api.postpaid_access@1 before registration. Enrollment is an authenticated merchant decision, not a payment. Record usage only from trusted servers. Finalize only after the exact current period ends; 100 net units rate to IDR 250 after one aggregate rounding step.