Privacy Policy

Last updated: August 23, 2026

Queue Cards is a spaced-repetition study app. This page explains what data the app collects, what it does not collect, and who else ever sees it.

Your study data stays on your device

Your decks, cards, and review history live only in local storage on your device. Queue Cards does not upload this data to any server. The one exception is cloud backup: if you turn it on, the backup file you create is uploaded to our storage so you can restore it on another device. You control when a backup happens. No background upload of your study data happens without you starting it.

Account data

Creating an account requires an email address. You can sign in through our authentication provider (Supabase), or through Sign in with Apple or Google, at your choice. We store:

• Your email address and sign-in identifier.
• Your subscription tier and AI usage totals. We use these only to enforce usage limits.
• Your cloud backup file, only if you choose to create one.

AI features

AI features are optional and off by default. When you use one, we send the specific content involved to our AI provider, Concentrate.ai, to generate a response. This content might be a card's front and back text, a chat message, or a topic name. We do not send your account identity, email, or any other personal data alongside that request.

If you provide your own AI provider API key (BYOK), we store that key only in your device's secure keychain or keystore. It is never sent to our servers.

Paid subscribers can turn on Zero Data Retention. This setting routes AI requests through provider infrastructure certified not to retain request content after the response is generated. It is opt-in and off by default.

Optional engine-tuning data

Queue Cards can send us real review data to help tune the FSRS scheduling engine. This is off by default, and it is not part of any other setting — turning it on takes a deliberate trip into Settings to find it. We do not ask for this anywhere else in the app.

If you turn it on, we send: which card was reviewed (as a random id with no card content attached), what rating you gave it, its learning state, how many days since its last review, how many days until its next review, and when that happened. We also send your own saved FSRS settings (retention target, interval limits, and the scheduler's own weights). We do not send your card text, deck names, or topic names.

This is never linked to your account or email, signed in or not. We generate a random id on your device the first time you turn this on, used only so we can tell which rows came from the same device over time — turning the setting off does not remove already-sent data, but you can reset that id from the same Settings screen at any point, which starts a fresh, unlinked history going forward.

Why you might turn it on: real review data from real study sessions is what makes the scheduling engine's defaults better for everyone, including you on a future update. Why you might leave it off: it is still data leaving your device, even without your identity attached, and that is a reasonable thing to simply not want. Neither choice affects any feature, limit, or price in the app.

Because this data is never linked to your account, our website cannot find or delete it for you. Delete it from the same place you turned it on: Settings → Engine Research → Delete my data, on the device that sent it.

What we do not do

Who we share data with

We use a small number of service providers to run the app. Each one only receives what it needs for its specific purpose.

• Supabase — hosts our database, authentication, and backend functions.
• Concentrate.ai — processes AI feature requests. It receives only the specific content involved in that request.
• RevenueCat — manages subscriptions and purchase validation with Apple and Google.
• Apple / Google — process payments. They also handle sign-in if you choose that option.

None of these providers may use your data for their own purposes.

Bug reports

A bug report may include a screenshot and a description you write, along with your app version and platform. We keep bug reports to fix the underlying problem. A bug report is never linked to your account, whether or not you're signed in when you send it — there is no personal identifier attached to it to begin with.

Account deletion and cloud backup deletion

You can delete your account and its server-side data at any time. Use Settings inside the app, or our account deletion page. Deleting your account removes your account, sign-in credentials, subscription record, and any cloud backup. If you only want your cloud backup gone and want to keep your account, that page also offers that on its own. Your local decks, cards, and review history are not affected by either, since Queue Cards never uploads them except inside a cloud backup you started yourself.

Engine-tuning data (above) is the one exception: since it is never linked to your account, deleting your account does not delete it. Delete it from the app itself, on the device that sent it, before you delete your account or lose access to that device.

Children's privacy

Queue Cards is not directed at children under 13. We do not knowingly collect personal information from children under 13.

Changes to this policy

If this policy changes in a way that affects what data we collect or how we use it, we will update this page and change the date at the top.

Contact

Questions about this policy or your data: [email protected]