Is CardStack – Credit Card Offers safe to install?

What data it declares

The developer declares that it collects these kinds of data:

• Personally identifiable information such as name, address, email address or age
• Financial and payment information such as transactions, card numbers or credit history
• Authentication information such as passwords, credentials or PIN codes
• Location such as region, IP address or GPS coordinates
• User activity such as clicks, scrolling, keystrokes or network monitoring
• Website content such as text, images or links on the pages you open

The developer also certifies that your data is not sold to third parties outside approved uses, not used for purposes unrelated to the extension's core function, and not used to decide creditworthiness or lending.

The listing links to a privacy policy.

This is the developer's own declaration in the Chrome Web Store. We cannot check it against what the extension does.

What Chrome asks you to allow

When you add it, Chrome asks you to allow it to:

• Read and change your data on a number of websites
• Read your browsing history

Derived from the manifest by Chrome's documented rules; the dialog's exact wording depends on your Chrome version and language. Chrome asks again if an update requests more.

What it can reach

Specific sites only: 7 match patterns.

• https://cardstack-production.up.railway.app/* only cardstack-production.up.railway.app
• *://www.americanexpress.com/* only www.americanexpress.com
• *://global.americanexpress.com/* only global.americanexpress.com
• *://secure.chase.com/* only secure.chase.com
• *://ultimaterewardspoints.chase.com/* only ultimaterewardspoints.chase.com
• *://myaccounts.capitalone.com/* only myaccounts.capitalone.com
• *://www.bilt.com/* only www.bilt.com

Reaches your browsing data or every site

• See the address and title of every tab you have open tabs

Worth knowing

• Run its own code on the pages it can access scripting

Routine for an extension

• Act on the current tab, but only after you click it activeTab
• Open a panel beside the page sidePanel
• Store data in your browser storage

Pages it runs its code on

It runs its own code on specific pages only: 9 site patterns.

• *://www.americanexpress.com/* only www.americanexpress.com
• *://global.americanexpress.com/* only global.americanexpress.com
• *://secure.chase.com/* only secure.chase.com

A content script is code the extension injects into pages matching these patterns. On those pages it can read and change what you see, whether or not a host permission is listed above.

What it may ask for later

Not granted when you add it: Chrome asks you the moment the extension requests one of these, and you can refuse. It may later ask for access to every site.

• <all_urls> every site

How usual this is for its category

In Lifestyle · Shopping, 19% of extensions ask for access to every site. This one: Access to specific sites only.

The typical extension there declares 2 browser permissions; this one declares 5 browser permissions.

• See the address and title of every tab you have open (tabs): 26% of extensions in this category ask for it.

Counted over the live extensions of the same category after our latest full pass of the store. A share is context, not a verdict: what is normal depends on what the extension is for.

Who uses it and how it is kept up

89 users

• Last updated in the store 95 days ago, on 2026-07-30.
• No new version in the last 90 days.

What the store shows

• Established publisher The store's badge for publishers with a good record and no history of violations.

The listing says it offers in-app purchases.

Has it asked for more over time?

This is the question a permission list on its own cannot answer. An extension that shipped narrow and widened later is a different proposition from one that always asked for the same thing.

The permissions this extension requests have not changed since we started watching it.

Who publishes it

CardStack. This listing has been in the store since 2026-03-18 and was last updated on 2026-07-30.

Similar extensions that ask for less

Listings close to this one in what they say they do, which declare less reach. Less reach is not a verdict on either: compare what each needs for the job.

1. Cherry Pick - Maximize Credit Card Rewards Runs its code on every site · 2 permissions 259 users ★ 3.6
2. EarnMore Runs its code on every site · 3 permissions, 3 site patterns 7 users (last published figure) ★ 5.0
3. Card Advisor Runs its code on every site · 3 permissions, 8 site patterns 4 users

How to check or remove it in Chrome

1. Type chrome://extensions in the address bar and find the extension in the list.
2. Open its details. The site access setting shows where it can run; set it to run only on click and it reaches a page only after you press its icon.
3. To uninstall it, choose Remove on the same page.

Questions people ask

What can CardStack – Credit Card Offers access?

Specific sites only: 7 match patterns. It declares 5 browser permissions.

What data does CardStack – Credit Card Offers collect?

The developer declares that it collects these kinds of data: Personally identifiable information, Financial and payment information, Authentication information, Location, User activity, Website content. This is the developer's own declaration in the Chrome Web Store. We cannot check it against what the extension does.

Has CardStack – Credit Card Offers asked for more permissions over time?

The permissions this extension requests have not changed since we started watching it.

Does CardStack – Credit Card Offers publish a privacy policy?

Yes, the store listing links to a privacy policy.