diff --git a/src/services/ProductStripeService.js b/src/services/ProductStripeService.js
index 07aacd6..c3023ff 100644
--- a/src/services/ProductStripeService.js
+++ b/src/services/ProductStripeService.js
@@ -152,9 +152,10 @@ export class ProductStripeService {
     if (Array.isArray(updates.variants)) {
       const incomingVariants = updates.variants
       const existingVariants = Array.isArray(existingProduct.variants) ? existingProduct.variants : []
+      const existingVariantsMap = new Map(existingVariants.filter(ev => ev.id).map(ev => [ev.id, ev]))
 
       const results = await Promise.all(incomingVariants.map(async (v) => {
-        const prior = v.id ? existingVariants.find(ev => ev.id === v.id) : undefined
+        const prior = v.id ? existingVariantsMap.get(v.id) : undefined
         const wantsCustom = !!v.hasCustomPrice && typeof v.price === 'number' && v.price > 0
 
         if (wantsCustom) {
@@ -200,9 +201,10 @@ export class ProductStripeService {
     if (Array.isArray(updates.variants2)) {
       const incomingVariants = updates.variants2
       const existingVariants = Array.isArray(existingProduct.variants2) ? existingProduct.variants2 : []
+      const existingVariantsMap = new Map(existingVariants.filter(ev => ev.id).map(ev => [ev.id, ev]))
 
       const results = await Promise.all(incomingVariants.map(async (v) => {
-        const prior = v.id ? existingVariants.find(ev => ev.id === v.id) : undefined
+        const prior = v.id ? existingVariantsMap.get(v.id) : undefined
         const wantsCustom = !!v.hasCustomPrice && typeof v.price === 'number' && v.price > 0
 
         if (wantsCustom) {
diff --git a/tests/services/ProductStripeService.perf.test.js b/tests/services/ProductStripeService.perf.test.js
new file mode 100644
index 0000000..8a18523
--- /dev/null
+++ b/tests/services/ProductStripeService.perf.test.js
@@ -0,0 +1,61 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { ProductStripeService } from '../../src/services/ProductStripeService.js'
+
+class MockStripeService {
+  async createProduct() { return { id: 'prod_123' } }
+  async createPrice(data) { return { id: `price_${Math.random()}` } }
+  async archivePrice() { return true }
+}
+
+describe('ProductStripeService Performance', () => {
+  let stripeService
+  let productStripeService
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+    stripeService = new MockStripeService()
+    productStripeService = new ProductStripeService(stripeService)
+  })
+
+  it('should verify variant update performance', async () => {
+    // Generate a large number of existing variants
+    const NUM_VARIANTS = 10000;
+    const existingVariants = Array.from({ length: NUM_VARIANTS }).map((_, i) => ({
+      id: `var_${i}`,
+      name: `Variant ${i}`,
+      price: 10 + i,
+      hasCustomPrice: true,
+      stripePriceId: `price_${i}`
+    }));
+
+    const existingVariants2 = Array.from({ length: NUM_VARIANTS }).map((_, i) => ({
+      id: `var2_${i}`,
+      name: `Variant2 ${i}`,
+      price: 100 + i,
+      hasCustomPrice: true,
+      stripePriceId: `price2_${i}`
+    }));
+
+    const existingProduct = {
+      stripeProductId: 'prod_123',
+      stripePriceId: 'base_price_123',
+      variants: existingVariants,
+      variants2: existingVariants2
+    };
+
+    // Updates with the same variants, to trigger the O(N^2) behavior
+    const updates = {
+      variants: existingVariants.map(v => ({ ...v, price: v.price + 1 })),
+      variants2: existingVariants2.map(v => ({ ...v, price: v.price + 1 }))
+    };
+
+    console.log(`--- Starting Performance Test with ${NUM_VARIANTS} variants (primary and secondary) ---`);
+    const start = performance.now();
+    await productStripeService.updateProductVariants(existingProduct, updates, stripeService);
+    const end = performance.now();
+
+    console.log(`Update time: ${(end - start).toFixed(2)}ms`);
+
+    expect(true).toBe(true);
+  })
+})