4 changed files with 410 additions and 11 deletions
--- a/apps/worker/src/main.ts
+++ b/apps/worker/src/main.ts
@@ -1,20 +1,29 @@
 import { loadConfig } from "@nproxy/config";
-import { createPrismaWorkerStore, prisma } from "@nproxy/db";
-import { createNanoBananaSimulatedAdapter } from "@nproxy/providers";
+import { createPrismaBillingStore, createPrismaWorkerStore, prisma } from "@nproxy/db";
+import {
+  createEmailTransport,
+  createNanoBananaSimulatedAdapter,
+  createPaymentProviderAdapter,
+} from "@nproxy/providers";

 const config = loadConfig();
 const intervalMs = config.keyPool.balancePollSeconds * 1000;
+const renewalLeadTimeHours = 72;
 const workerStore = createPrismaWorkerStore(prisma, {
  cooldownMinutes: config.keyPool.cooldownMinutes,
  failuresBeforeManualReview: config.keyPool.failuresBeforeManualReview,
 });
+const billingStore = createPrismaBillingStore(prisma);
 const nanoBananaAdapter = createNanoBananaSimulatedAdapter();
+const paymentProviderAdapter = createPaymentProviderAdapter(config.payment);
+const emailTransport = createEmailTransport(config.email);
 let isTickRunning = false;

 console.log(
  JSON.stringify({
    service: "worker",
    balancePollSeconds: config.keyPool.balancePollSeconds,
+    renewalLeadTimeHours,
    providerModel: config.provider.nanoBananaDefaultModel,
  }),
 );
@@ -44,6 +53,54 @@ async function runTick(): Promise<void> {
  isTickRunning = true;

  try {
+    const expiredInvoices = await billingStore.expireElapsedPendingInvoices();
+
+    if (expiredInvoices.expiredCount > 0) {
+      console.log(
+        JSON.stringify({
+          service: "worker",
+          event: "pending_invoices_expired",
+          expiredCount: expiredInvoices.expiredCount,
+        }),
+      );
+    }
+
+    const renewalNotifications = await billingStore.createUpcomingRenewalInvoices({
+      paymentProvider: config.payment.provider,
+      paymentProviderAdapter,
+      renewalLeadTimeHours,
+    });
+
+    for (const notification of renewalNotifications) {
+      const billingUrl = new URL("/billing", config.urls.appBaseUrl);
+      await emailTransport.send({
+        to: notification.email,
+        subject: "Your nproxy subscription renewal invoice",
+        text: [
+          "Your current subscription period is ending soon.",
+          `Current access ends at ${notification.subscriptionCurrentPeriodEnd.toISOString()}.`,
+          `Invoice amount: ${notification.invoice.amountCrypto} ${notification.invoice.currency}.`,
+          ...(notification.invoice.paymentAddress
+            ? [`Payment address: ${notification.invoice.paymentAddress}.`]
+            : []),
+          ...(notification.invoice.expiresAt
+            ? [`Invoice expires at ${notification.invoice.expiresAt.toISOString()}.`]
+            : []),
+          `Open billing: ${billingUrl.toString()}`,
+        ].join("\n"),
+      });
+    }
+
+    if (renewalNotifications.length > 0) {
+      console.log(
+        JSON.stringify({
+          service: "worker",
+          event: "renewal_invoices_created",
+          createdCount: renewalNotifications.length,
+        }),
+      );
+    }
+
    const recovery = await workerStore.recoverCooldownProviderKeys();

    if (recovery.recoveredCount > 0) {
--- a/docs/ops/payment-system.md
+++ b/docs/ops/payment-system.md
@@ -10,8 +10,11 @@ The current payment system covers:
 - default subscription plan bootstrap
 - user subscription creation at registration time
 - invoice creation through a provider adapter
+- automatic renewal-invoice creation `72 hours` before `currentPeriodEnd`
+- one renewal-invoice creation attempt per paid cycle unless the user explicitly creates a new one manually
 - manual admin activation after an operator verifies that the provider reported a final successful payment status
 - automatic expiry of elapsed subscription periods during account and generation access checks
+- automatic expiry of elapsed pending invoices
 - quota-cycle reset on successful activation

 The current payment system does not yet cover:
@@ -94,6 +97,17 @@ Current runtime note:
 5. The returned provider invoice data is persisted as a new local `PaymentInvoice` in `pending`.
 6. The API returns invoice details, including provider invoice id, amount, address, and expiry time.

+## Automatic renewal invoice flow
+1. The worker scans `active` manual-renewal subscriptions.
+2. If `currentPeriodEnd` is within the next `72 hours`, the worker checks whether the current paid cycle already has an invoice.
+3. If the current cycle has no invoice yet, the worker creates one renewal invoice through the payment-provider adapter.
+4. The worker sends the invoice details to the user by email.
+5. If any invoice already exists for the current cycle, the worker does not auto-create another one.
+
+Current rule:
+- after the first invoice exists for the current paid cycle, automatic re-creation stops for that cycle
+- if that invoice later expires or is canceled, the next invoice is created only when the user explicitly goes to billing and creates one
+
 ## Payment status semantics
 - `pending` does not count as paid.
 - `pending` does not activate the subscription.
@@ -104,6 +118,7 @@ Current runtime note:
 ## Invoice listing flow
 - `GET /api/billing/invoices` returns the user's invoices ordered by newest first.
 - This is a read-only view over persisted `PaymentInvoice` rows.
+- The worker also marks `pending` invoices `expired` when `expiresAt` has passed.

 ## Current activation flow
 The implemented activation path is manual and admin-driven.
--- a/packages/db/src/billing-store.test.ts
+++ b/packages/db/src/billing-store.test.ts
@@ -3,6 +3,97 @@ import assert from "node:assert/strict";
 import { Prisma } from "@prisma/client";
 import { BillingError, createPrismaBillingStore } from "./billing-store.js";

+test("createUpcomingRenewalInvoices creates one invoice for subscriptions entering the 72h renewal window", async () => {
+  const database = createRenewalBillingDatabase({
+    subscriptions: [
+      createRenewalSubscriptionFixture({
+        id: "subscription_1",
+        currentPeriodStart: new Date("2026-03-01T12:00:00.000Z"),
+        currentPeriodEnd: new Date("2026-03-12T11:00:00.000Z"),
+      }),
+    ],
+  });
+  const store = createPrismaBillingStore(database.client);
+
+  const notifications = await store.createUpcomingRenewalInvoices({
+    paymentProvider: "nowpayments",
+    paymentProviderAdapter: {
+      createInvoice: async () => ({
+        providerInvoiceId: "provider_invoice_renewal_1",
+        paymentAddress: "wallet_renewal_1",
+        amountCrypto: 29,
+        amountUsd: 29,
+        currency: "USDT",
+        expiresAt: new Date("2026-03-10T13:00:00.000Z"),
+      }),
+    },
+    renewalLeadTimeHours: 72,
+    now: new Date("2026-03-09T12:00:00.000Z"),
+  });
+
+  assert.equal(notifications.length, 1);
+  assert.equal(notifications[0]?.email, "user_subscription_1@example.com");
+  assert.equal(notifications[0]?.subscriptionId, "subscription_1");
+  assert.equal(database.calls.paymentInvoiceCreate.length, 1);
+});
+
+test("createUpcomingRenewalInvoices does not auto-create another invoice after one already exists in the current cycle", async () => {
+  const currentPeriodStart = new Date("2026-03-01T12:00:00.000Z");
+  const database = createRenewalBillingDatabase({
+    subscriptions: [
+      createRenewalSubscriptionFixture({
+        id: "subscription_1",
+        currentPeriodStart,
+        currentPeriodEnd: new Date("2026-03-12T11:00:00.000Z"),
+      }),
+    ],
+    existingInvoicesBySubscriptionId: {
+      subscription_1: [
+        createInvoiceFixture({
+          id: "invoice_existing",
+          status: "expired",
+          createdAt: new Date("2026-03-09T09:00:00.000Z"),
+          paidAt: null,
+          subscription: createSubscriptionFixture({
+            id: "subscription_1",
+            currentPeriodStart,
+            currentPeriodEnd: new Date("2026-03-12T11:00:00.000Z"),
+            status: "active",
+          }),
+        }),
+      ],
+    },
+  });
+  const store = createPrismaBillingStore(database.client);
+
+  const notifications = await store.createUpcomingRenewalInvoices({
+    paymentProvider: "nowpayments",
+    paymentProviderAdapter: {
+      createInvoice: async () => {
+        throw new Error("createInvoice should not be called");
+      },
+    },
+    renewalLeadTimeHours: 72,
+    now: new Date("2026-03-09T12:00:00.000Z"),
+  });
+
+  assert.equal(notifications.length, 0);
+  assert.equal(database.calls.paymentInvoiceCreate.length, 0);
+});
+
+test("expireElapsedPendingInvoices marks pending invoices expired", async () => {
+  const database = createRenewalBillingDatabase({
+    subscriptions: [],
+    expirePendingCount: 2,
+  });
+  const store = createPrismaBillingStore(database.client);
+
+  const result = await store.expireElapsedPendingInvoices(new Date("2026-03-10T12:00:00.000Z"));
+
+  assert.equal(result.expiredCount, 2);
+  assert.equal(database.calls.paymentInvoiceExpireUpdateMany.length, 1);
+});
+
 test("markInvoicePaid activates a pending invoice once and writes an admin audit log", async () => {
  const invoice = createInvoiceFixture({
    status: "pending",
@@ -234,12 +325,14 @@ function createBillingDatabase(input: {
 }

 function createInvoiceFixture(input: {
+  id?: string;
  status: "pending" | "paid" | "expired" | "canceled";
  paidAt: Date | null;
+  createdAt?: Date;
  subscription: ReturnType<typeof createSubscriptionFixture> | null;
 }) {
  return {
-    id: "invoice_1",
+    id: input.id ?? "invoice_1",
    userId: "user_1",
    subscriptionId: input.subscription?.id ?? null,
    provider: "nowpayments",
@@ -251,22 +344,30 @@ function createInvoiceFixture(input: {
    paymentAddress: "wallet_1",
    expiresAt: new Date("2026-03-11T12:00:00.000Z"),
    paidAt: input.paidAt,
-    createdAt: new Date("2026-03-10T11:00:00.000Z"),
-    updatedAt: new Date("2026-03-10T11:00:00.000Z"),
+    createdAt: input.createdAt ?? new Date("2026-03-10T11:00:00.000Z"),
+    updatedAt: input.createdAt ?? new Date("2026-03-10T11:00:00.000Z"),
    subscription: input.subscription,
  };
 }

-function createSubscriptionFixture() {
+function createSubscriptionFixture(
+  overrides?: Partial<{
+    id: string;
+    status: "pending_activation" | "active" | "expired";
+    currentPeriodStart: Date | null;
+    currentPeriodEnd: Date | null;
+    activatedAt: Date | null;
+  }>,
+) {
  return {
-    id: "subscription_1",
+    id: overrides?.id ?? "subscription_1",
    userId: "user_1",
    planId: "plan_1",
-    status: "pending_activation" as const,
+    status: overrides?.status ?? ("pending_activation" as const),
    renewsManually: true,
-    activatedAt: null,
-    currentPeriodStart: null,
-    currentPeriodEnd: null,
+    activatedAt: overrides?.activatedAt ?? null,
+    currentPeriodStart: overrides?.currentPeriodStart ?? null,
+    currentPeriodEnd: overrides?.currentPeriodEnd ?? null,
    canceledAt: null,
    createdAt: new Date("2026-03-10T11:00:00.000Z"),
    updatedAt: new Date("2026-03-10T11:00:00.000Z"),
@@ -283,3 +384,104 @@ function createSubscriptionFixture() {
    },
  };
 }
+
+function createRenewalBillingDatabase(input: {
+  subscriptions: Array<ReturnType<typeof createRenewalSubscriptionFixture>>;
+  existingInvoicesBySubscriptionId?: Record<string, ReturnType<typeof createInvoiceFixture>[]>;
+  expirePendingCount?: number;
+}) {
+  const calls = {
+    paymentInvoiceCreate: [] as Array<Record<string, unknown>>,
+    paymentInvoiceFindFirst: [] as Array<Record<string, unknown>>,
+    paymentInvoiceExpireUpdateMany: [] as Array<Record<string, unknown>>,
+  };
+
+  const client = {
+    subscription: {
+      findMany: async () => input.subscriptions,
+    },
+    paymentInvoice: {
+      findFirst: async ({
+        where,
+      }: {
+        where: {
+          subscriptionId: string;
+          createdAt: { gte: Date };
+        };
+      }) => {
+        calls.paymentInvoiceFindFirst.push({ where });
+        const invoices = input.existingInvoicesBySubscriptionId?.[where.subscriptionId] ?? [];
+        return (
+          invoices
+            .filter((invoice) => invoice.createdAt >= where.createdAt.gte)
+            .sort((left, right) => right.createdAt.getTime() - left.createdAt.getTime())[0] ?? null
+        );
+      },
+      create: async ({ data }: { data: Record<string, unknown> }) => {
+        calls.paymentInvoiceCreate.push({ data });
+        return {
+          id: "invoice_created_1",
+          subscriptionId: data.subscriptionId as string,
+          provider: data.provider as string,
+          providerInvoiceId: data.providerInvoiceId as string,
+          status: "pending" as const,
+          currency: data.currency as string,
+          amountCrypto: new Prisma.Decimal(String(data.amountCrypto)),
+          amountUsd: new Prisma.Decimal(String(data.amountUsd)),
+          paymentAddress: data.paymentAddress as string,
+          expiresAt: data.expiresAt as Date,
+          paidAt: null,
+          createdAt: new Date("2026-03-09T12:00:00.000Z"),
+          updatedAt: new Date("2026-03-09T12:00:00.000Z"),
+        };
+      },
+      updateMany: async ({
+        where,
+        data,
+      }: {
+        where: { status: "pending"; expiresAt: { lte: Date } };
+        data: { status: "expired" };
+      }) => {
+        calls.paymentInvoiceExpireUpdateMany.push({ where, data });
+        return { count: input.expirePendingCount ?? 0 };
+      },
+    },
+  } as unknown as Parameters<typeof createPrismaBillingStore>[0];
+
+  return {
+    client,
+    calls,
+  };
+}
+
+function createRenewalSubscriptionFixture(input: {
+  id: string;
+  currentPeriodStart: Date;
+  currentPeriodEnd: Date;
+}) {
+  return {
+    id: input.id,
+    userId: `user_${input.id}`,
+    planId: "plan_1",
+    status: "active" as const,
+    renewsManually: true,
+    activatedAt: input.currentPeriodStart,
+    currentPeriodStart: input.currentPeriodStart,
+    currentPeriodEnd: input.currentPeriodEnd,
+    canceledAt: null,
+    createdAt: input.currentPeriodStart,
+    updatedAt: input.currentPeriodStart,
+    user: {
+      id: `user_${input.id}`,
+      email: `user_${input.id}@example.com`,
+    },
+    plan: {
+      id: "plan_1",
+      code: "monthly",
+      displayName: "Monthly",
+      monthlyRequestLimit: 100,
+      monthlyPriceUsd: new Prisma.Decimal("29"),
+      billingCurrency: "USDT",
+    },
+  };
+}
--- a/packages/db/src/billing-store.ts
+++ b/packages/db/src/billing-store.ts
@@ -48,6 +48,18 @@ export interface BillingActorMetadata {
  ref?: string;
 }

+export interface ExpirePendingInvoicesResult {
+  expiredCount: number;
+}
+
+export interface RenewalInvoiceNotification {
+  userId: string;
+  email: string;
+  subscriptionId: string;
+  subscriptionCurrentPeriodEnd: Date;
+  invoice: BillingInvoiceRecord;
+}
+
 export class BillingError extends Error {
  constructor(
    readonly code: "invoice_not_found" | "invoice_transition_not_allowed",
@@ -147,6 +159,115 @@ export function createPrismaBillingStore(database: PrismaClient = defaultPrisma)
      return mapInvoice(invoice);
    },

+    async expireElapsedPendingInvoices(
+      now: Date = new Date(),
+    ): Promise<ExpirePendingInvoicesResult> {
+      const result = await database.paymentInvoice.updateMany({
+        where: {
+          status: "pending",
+          expiresAt: {
+            lte: now,
+          },
+        },
+        data: {
+          status: "expired",
+        },
+      });
+
+      return {
+        expiredCount: result.count,
+      };
+    },
+
+    async createUpcomingRenewalInvoices(input: {
+      paymentProvider: string;
+      paymentProviderAdapter: PaymentProviderAdapter;
+      renewalLeadTimeHours: number;
+      now?: Date;
+    }): Promise<RenewalInvoiceNotification[]> {
+      const now = input.now ?? new Date();
+      const renewalWindowEnd = addHours(now, input.renewalLeadTimeHours);
+      const subscriptions = await database.subscription.findMany({
+        where: {
+          status: "active",
+          renewsManually: true,
+          currentPeriodEnd: {
+            gt: now,
+            lte: renewalWindowEnd,
+          },
+        },
+        include: {
+          user: true,
+          plan: true,
+        },
+        orderBy: {
+          currentPeriodEnd: "asc",
+        },
+      });
+
+      const notifications: RenewalInvoiceNotification[] = [];
+
+      for (const subscription of subscriptions) {
+        if (!subscription.currentPeriodEnd) {
+          continue;
+        }
+
+        const cycleStart =
+          subscription.currentPeriodStart ?? subscription.activatedAt ?? subscription.createdAt;
+        const existingCycleInvoice = await database.paymentInvoice.findFirst({
+          where: {
+            subscriptionId: subscription.id,
+            createdAt: {
+              gte: cycleStart,
+            },
+          },
+          orderBy: {
+            createdAt: "desc",
+          },
+        });
+
+        if (existingCycleInvoice) {
+          continue;
+        }
+
+        const amountUsd = subscription.plan.monthlyPriceUsd.toNumber();
+        const currency = subscription.plan.billingCurrency;
+        const amountCrypto = amountUsd;
+        const providerInvoice = await input.paymentProviderAdapter.createInvoice({
+          userId: subscription.userId,
+          planCode: subscription.plan.code,
+          amountUsd,
+          amountCrypto,
+          currency,
+        });
+
+        const invoice = await database.paymentInvoice.create({
+          data: {
+            userId: subscription.userId,
+            subscriptionId: subscription.id,
+            provider: input.paymentProvider,
+            providerInvoiceId: providerInvoice.providerInvoiceId,
+            status: "pending",
+            currency: providerInvoice.currency,
+            amountCrypto: new Prisma.Decimal(providerInvoice.amountCrypto),
+            amountUsd: new Prisma.Decimal(providerInvoice.amountUsd),
+            paymentAddress: providerInvoice.paymentAddress,
+            expiresAt: providerInvoice.expiresAt,
+          },
+        });
+
+        notifications.push({
+          userId: subscription.userId,
+          email: subscription.user.email,
+          subscriptionId: subscription.id,
+          subscriptionCurrentPeriodEnd: subscription.currentPeriodEnd,
+          invoice: mapInvoice(invoice),
+        });
+      }
+
+      return notifications;
+    },
+
    async markInvoicePaid(input: {
      invoiceId: string;
      actor?: BillingActorMetadata;
@@ -376,3 +497,7 @@ function mapSubscription(subscription: {
 function addDays(value: Date, days: number): Date {
  return new Date(value.getTime() + days * 24 * 60 * 60 * 1000);
 }
+
+function addHours(value: Date, hours: number): Date {
+  return new Date(value.getTime() + hours * 60 * 60 * 1000);
+}