Card Optimizer

Legal

Privacy policy

Last updated October 18, 2026. See also the terms.

Card Optimizer suggests which of your credit cards to use for a purchase. It never asks for card numbers, bank logins or anything that could be used to spend money, and it doesn’t show ads or track you across other apps and websites.

What we store

  • Which cards you hold, by product name (for example “Amex Gold”), the bonus categories you picked on cards that let you choose, how much you’ve spent toward bonus caps this period, and a yearly total of what the purchases you logged earned less than your best card would have (how many, and the dollar amount, not the purchases themselves).
  • If you create an account: your email address and a one-way hash of your password (we can’t read the password itself), plus records of your signed-in sessions.
  • If you sign in with Google: Google tells us your email address and an ID for your Google account, which we keep to recognize you next time. We don’t get your password, name, photo, contacts or anything else from your Google account, and we don’t post anything there.
  • If you don’t: a random ID generated on your device, so your cards are remembered there. It isn’t linked to your name, email or device identifiers.
  • Store names the app doesn’t know. When you look up a merchant that isn’t in the list, the name you typed is counted so we know which stores to add. Only the name, a count and when it was first and last looked up are kept, with no ID, account or device attached.

Otherwise, purchases you compare are not stored unless you tap “I used this card”, which adds the amount to your bonus-cap totals and counts it in your yearly missed-savings total. The app also keeps a copy of your cards on your device so it can open without a connection.

How it’s used

To show you recommendations and keep your cards in sync across your devices, and, on the website, to count visits and taps so we can see what’s used (below). We don’t sell or share your data, and we don’t use it for advertising.

Visit counts

The website (not the iPhone app) uses Umami (umami.is), a privacy-friendly analytics service that sets no cookies, to count page visits and a few taps: finding the best card (and whether by category or store), sharing results, creating an account and choosing Google sign-in. With each one it receives the page address without the part after “?”, the site that linked you, your browser, operating system, screen size, language and approximate location worked out from your IP address. It doesn’t receive your cards, amounts, store names, email or anything you type, and it can’t recognize you on other websites. Umami doesn’t use cookies or IDs on your device; it tells visits apart with a code made from your IP address and browser that changes every month. If your browser sends Do Not Track, or blocks the counter, nothing is counted. Umami keeps these counts for six months.

Who else handles it

The app and its database are hosted by Render (render.com) in the United States. Like any web server, it receives your IP address with each request; this is used briefly in memory to limit repeated sign-in attempts and may appear in the host’s request logs. Render stores and processes this data on our behalf only to run the app, and we hold it to the same protections described here. If you choose to sign in with Google, Google handles that sign-in under its own privacy policy and learns that you signed in to Card Optimizer. Umami counts website visits as described above. We don’t share your data with anyone else, use advertising SDKs, or send it to AI services.

How long we keep it

Your account and the cards, picks, cap totals and missed-savings totals saved with it are kept until you delete them. Sign-in sessions expire after 30 days, or when you sign out. Cards saved without an account are kept until you remove them.

Cookies and storage on your device

Signed in on the website, the app sets one cookie, which keeps you signed in. Your device also keeps the anonymous ID, a copy of your cards for offline use and your light or dark theme choice. All of this is needed for the app to work, none of it is used for tracking or advertising, and nothing is set by anyone else, so there’s no cookie banner to accept. The visit counter stores nothing on your device.

When you share a comparison, the link contains the cards, purchase category or store, amount and date it shows. It contains nothing that identifies you. Anyone you send it to can open it.

Signed in, choose Delete account at the top of the app. That deletes your account, email, cards, picks, cap totals and missed-savings totals right away and signs you out on every device. Without an account, choose Delete my data at the top of the app. That deletes the cards, picks, cap totals and missed-savings totals saved for your device right away and starts a new anonymous ID. Uninstalling the app or clearing your browser’s site data removes the ID and copy from your device. If you signed in with Google, you can also remove Card Optimizer from your Google account’s connections.

Children

Card Optimizer is meant for adults and isn’t directed at children under 13. You need to be 18 or older to create an account. If you believe a child has given us information, email us and we’ll delete it.

Changes and contact

If this policy changes, the date at the top will change with it. Questions, or a request to delete data you can’t reach in the app: email [email protected].