diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1995cebd9..a731397a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Randomized the placeholder in the assistant
 - Filtered out sectors with zero weight for ETF and mutual fund assets in the _Yahoo Finance_ data enhancer
 - Enabled the _Bull Dashboard_ in the admin control panel without requiring an environment variable (experimental)
+- Improved the verification of the _Stripe_ checkout session when creating a subscription
 - Relaxed the URL validation in the asset profile DTOs to accept both `HTTP` and `HTTPS` protocols
 - Relaxed the URL validation in the platform DTOs to accept both `HTTP` and `HTTPS` protocols
 - Extracted the page tabs to a reusable component
diff --git a/apps/api/src/app/subscription/subscription.controller.ts b/apps/api/src/app/subscription/subscription.controller.ts
index e1c705fdd..3e6316ec6 100644
--- a/apps/api/src/app/subscription/subscription.controller.ts
+++ b/apps/api/src/app/subscription/subscription.controller.ts
@@ -100,10 +100,12 @@ export class SubscriptionController {
       request.query.checkoutSessionId as string
     );
 
-    Logger.log(
-      `Subscription for user '${userId}' has been created via Stripe`,
-      'SubscriptionController'
-    );
+    if (userId) {
+      Logger.log(
+        `Subscription for user '${userId}' has been created via Stripe`,
+        'SubscriptionController'
+      );
+    }
 
     response.redirect(
       `${this.configurationService.get(
diff --git a/apps/api/src/app/subscription/subscription.service.ts b/apps/api/src/app/subscription/subscription.service.ts
index 07795d0d1..557d81976 100644
--- a/apps/api/src/app/subscription/subscription.service.ts
+++ b/apps/api/src/app/subscription/subscription.service.ts
@@ -17,7 +17,7 @@ import {
 } from '@ghostfolio/common/types';
 
 import { Injectable, Logger } from '@nestjs/common';
-import { Subscription } from '@prisma/client';
+import { Prisma, Subscription } from '@prisma/client';
 import { addMilliseconds, isBefore } from 'date-fns';
 import ms, { StringValue } from 'ms';
 import Stripe from 'stripe';
@@ -108,11 +108,13 @@ export class SubscriptionService {
     duration = '1 year',
     durationExtension,
     price,
+    stripeCheckoutSessionId,
     userId
   }: {
     duration?: StringValue;
     durationExtension?: StringValue;
     price: number;
+    stripeCheckoutSessionId?: string;
     userId: string;
   }) {
     let expiresAt = addMilliseconds(new Date(), ms(duration));
@@ -125,6 +127,7 @@ export class SubscriptionService {
       data: {
         expiresAt,
         price,
+        stripeCheckoutSessionId,
         user: {
           connect: {
             id: userId
@@ -136,25 +139,42 @@ export class SubscriptionService {
 
   public async createSubscriptionViaStripe(aCheckoutSessionId: string) {
     try {
-      let durationExtension: StringValue;
-
       const session =
         await this.stripe.checkout.sessions.retrieve(aCheckoutSessionId);
 
+      if (session.payment_status !== 'paid' || session.status !== 'complete') {
+        throw new Error(
+          `Stripe Checkout Session '${aCheckoutSessionId}' has not been paid (status=${session.status}, payment_status=${session.payment_status})`
+        );
+      }
+
       const subscriptionOffer: SubscriptionOffer = JSON.parse(
         session.metadata.subscriptionOffer ?? '{}'
       );
 
-      if (subscriptionOffer) {
-        durationExtension = subscriptionOffer.durationExtension;
+      const durationExtension = subscriptionOffer?.durationExtension;
+
+      try {
+        await this.createSubscription({
+          durationExtension,
+          price: session.amount_total / 100,
+          stripeCheckoutSessionId: session.id,
+          userId: session.client_reference_id
+        });
+      } catch (error) {
+        if (
+          error instanceof Prisma.PrismaClientKnownRequestError &&
+          error.code === 'P2002'
+        ) {
+          Logger.log(
+            `Stripe Checkout Session '${session.id}' has already been redeemed`,
+            'SubscriptionService'
+          );
+        } else {
+          throw error;
+        }
       }
 
-      await this.createSubscription({
-        durationExtension,
-        price: session.amount_total / 100,
-        userId: session.client_reference_id
-      });
-
       return session.client_reference_id;
     } catch (error) {
       Logger.error(error, 'SubscriptionService');
diff --git a/prisma/migrations/20260516074856_added_stripe_checkout_session_to_subscription/migration.sql b/prisma/migrations/20260516074856_added_stripe_checkout_session_to_subscription/migration.sql
new file mode 100644
index 000000000..f5c8ae016
--- /dev/null
+++ b/prisma/migrations/20260516074856_added_stripe_checkout_session_to_subscription/migration.sql
@@ -0,0 +1,5 @@
+-- AlterTable
+ALTER TABLE "Subscription" ADD COLUMN "stripeCheckoutSessionId" TEXT;
+
+-- CreateIndex
+CREATE UNIQUE INDEX "Subscription_stripeCheckoutSessionId_key" ON "Subscription"("stripeCheckoutSessionId");
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index a739ce8ff..024ab7aa0 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -236,13 +236,14 @@ model SymbolProfileOverrides {
 }
 
 model Subscription {
-  createdAt DateTime @default(now())
-  expiresAt DateTime
-  id        String   @id @default(uuid())
-  price     Float?
-  updatedAt DateTime @updatedAt
-  user      User     @relation(fields: [userId], onDelete: Cascade, references: [id])
-  userId    String
+  createdAt               DateTime @default(now())
+  expiresAt               DateTime
+  id                      String   @id @default(uuid())
+  price                   Float?
+  stripeCheckoutSessionId String?  @unique
+  updatedAt               DateTime @updatedAt
+  user                    User     @relation(fields: [userId], onDelete: Cascade, references: [id])
+  userId                  String
 
   @@index([userId])
 }