Privacy Policy

Last updated: May 9, 2026

Card Brain Offer Batch Adder (“Card Brain”) is a Chrome extension that helps you add credit card offers on supported bank websites (American Express, Chase, Citi).

What we collect

Email address — provided when you start a free trial or subscribe. Used solely to manage your subscription via Stripe.

That’s it. Card Brain does not collect, store, or transmit any other personal data. It does not access your bank credentials, account numbers, transaction history, or any financial information.

How the extension works

• Scans the currently open offers page for visible “Add to Card” buttons.
• All scanning and clicking happens locally in your browser tab.
• No page content, offer data, or browsing activity is sent to any server.
• The extension only runs when you click “Scan” or “Add All” — it does not run in the background.

Subscription verification

To confirm your free trial or subscription is active, the extension stores a signed authentication token (JWT) locally in your browser and periodically queries our backend at https://cardbrain-web.vercel.app/api/me/entitlement (no more often than every 5 minutes per session). The request returns only your subscription state and trial-end date. The JWT contains your user identifier and an expiration timestamp; it does not contain payment data.

Permissions

• activeTab — access the current tab only when you click the extension.
• scripting — inject the scanner/runner script into the offers page.
• storage — store your authentication token (JWT) locally so you don’t have to sign in every time.
• tabs — detect which bank site you’re on to show the correct UI.
• host_permissions: cardbrain-web.vercel.app — lets the extension verify your subscription status and start the Stripe checkout flow on our backend. No host permissions are requested for any bank or third-party site.

Payments

Payments are processed by Stripe. Card Brain does not see or store your credit card number. Stripe handles all payment data under their own privacy policy.

Trial & subscription

• 30-day free trial. No credit card required.
• $14.99/year if you choose to subscribe after the trial.
• Cancel anytime from the Manage Subscription link in the extension.
• No refunds. Cancellation stops future renewals; your access continues until the end of the current billing period.

Data retention

If you uninstall the extension, all locally stored data (authentication token, settings) is deleted automatically by Chrome. Your account record (email + subscription state) is retained while your account is active. If you want your account data deleted, email cardbrain.support@gmail.com and we will delete it within 30 days. Your Stripe customer record is retained by Stripe per their own data retention policy.

Third-party services

• Stripe — payment processing and subscription management.
• Vercel — hosts the subscription API (no user data is stored on Vercel beyond what Stripe provides).

Card Brain does not use analytics, tracking, or advertising services.

Contact

Questions about this policy? Email cardbrain.support@gmail.com