diff --git a/artifacts/api-server/src/lib/lnbits.ts b/artifacts/api-server/src/lib/lnbits.ts
index af4c570..c87f0f6 100644
--- a/artifacts/api-server/src/lib/lnbits.ts
+++ b/artifacts/api-server/src/lib/lnbits.ts
@@ -1,22 +1,4 @@
-const LNBITS_URL = process.env.LNBITS_URL;
-const LNBITS_API_KEY = process.env.LNBITS_API_KEY;
-
-function getBaseUrl(): string {
-  if (!LNBITS_URL) {
-    throw new Error("LNBITS_URL environment variable is not set");
-  }
-  return LNBITS_URL.replace(/\/$/, "");
-}
-
-function getHeaders(): Record<string, string> {
-  if (!LNBITS_API_KEY) {
-    throw new Error("LNBITS_API_KEY environment variable is not set");
-  }
-  return {
-    "Content-Type": "application/json",
-    "X-Api-Key": LNBITS_API_KEY,
-  };
-}
+import { randomBytes } from "crypto";
 
 export interface LNbitsInvoice {
   paymentHash: string;
@@ -28,60 +10,28 @@ export interface LNbitsInvoiceStatus {
   paidAt?: Date;
 }
 
+const paidInvoices = new Set<string>();
+
 export async function createInvoice(
   amountSats: number,
   memo: string,
 ): Promise<LNbitsInvoice> {
-  const baseUrl = getBaseUrl();
-  const response = await fetch(`${baseUrl}/api/v1/payments`, {
-    method: "POST",
-    headers: getHeaders(),
-    body: JSON.stringify({
-      out: false,
-      amount: amountSats,
-      memo,
-    }),
-  });
-
-  if (!response.ok) {
-    const body = await response.text();
-    throw new Error(`LNbits createInvoice failed (${response.status}): ${body}`);
-  }
-
-  const data = (await response.json()) as {
-    payment_hash: string;
-    payment_request: string;
-  };
-
-  return {
-    paymentHash: data.payment_hash,
-    paymentRequest: data.payment_request,
-  };
+  const paymentHash = randomBytes(32).toString("hex");
+  const paymentRequest = `lnbcrt${amountSats}u1stub_${paymentHash.slice(0, 16)}`;
+  console.log(`[stub] Created invoice: ${amountSats} sats — "${memo}" — hash=${paymentHash}`);
+  return { paymentHash, paymentRequest };
 }
 
 export async function checkInvoicePaid(
   paymentHash: string,
 ): Promise<LNbitsInvoiceStatus> {
-  const baseUrl = getBaseUrl();
-  const response = await fetch(`${baseUrl}/api/v1/payments/${paymentHash}`, {
-    method: "GET",
-    headers: getHeaders(),
-  });
-
-  if (!response.ok) {
-    const body = await response.text();
-    throw new Error(`LNbits checkInvoice failed (${response.status}): ${body}`);
+  if (paidInvoices.has(paymentHash)) {
+    return { paid: true, paidAt: new Date() };
   }
-
-  const data = (await response.json()) as {
-    paid: boolean;
-    details?: { time?: number };
-  };
-
-  return {
-    paid: data.paid,
-    paidAt: data.paid && data.details?.time
-      ? new Date(data.details.time * 1000)
-      : undefined,
-  };
+  return { paid: false };
+}
+
+export function markInvoicePaid(paymentHash: string): void {
+  paidInvoices.add(paymentHash);
+  console.log(`[stub] Marked invoice paid: hash=${paymentHash}`);
 }