Your study data stays yours.

01

The short version

This summary is written for speed, not for precision. The sections that follow it are the operative ones.

We do not run advertising, we do not embed third-party tracking or attribution SDKs, we do not build advertising profiles, and we do not sell or share your personal information.

02

Who we are

recall is developed and published by Numinous Lab, an independent software and publishing studio. Where this policy says “we”, “us” or “our”, it means Numinous Lab. Where it says “recall”, it means the recall mobile application for iOS and Android (bundle identifier com.numinouslab.recall) and the hosted study content that the application downloads.

For the purposes of data protection law, Numinous Lab is the data controller for the limited personal information described in this policy. You can reach us at support@numinouslab.com.

03

Data that stays on your device

recall stores your study material in a local database on your device. This is the core of the product, not an afterthought: the application is built to work with the network switched off entirely. The following is written to that local database and is not transmitted to us:

• Recalls, decks, and their review schedules and review history.
• Your attempts at problems, including the answers and working you type.
• Explanations you write in the Feynman screen.
• Problems and problem sets you create yourself.
• Focus sessions and practice sessions, including their timings.
• Progress, mastery estimates and performance snapshots.
• Study plan preferences, reminder preferences and app settings.
• Study content packs you have downloaded for offline use.

Local usage events

recall records a small set of usage events locally so that the application can adapt sessions to your performance: session starts and ends, problem attempts and their outcome, download starts and completions, and errors. These rows carry identifiers, outcomes, counts and durations only — never the text of anything you have written.

04

The optional recall account

You can use recall for local study without an account. An account exists for two reasons: to connect your recall Pro subscription to an identity that survives a change of device, and to enable the optional encrypted backup described below.

Where you choose to create one, we process:

• Your email address — used to send you a sign-in link or a one-time sign-in code, and to contact you about your account or subscription if we need to. recall uses passwordless sign-in, so we never hold a password for you.
• An account identifier — a random identifier generated for your account, used internally to link your subscription entitlement and backup record.
• An optional display name, if you set one.
• Account timestamps — when the account was created and last updated.

We process this information to perform our contract with you: providing the account, the subscription entitlement, and the backup service you asked for. Signing out, or deleting your online account, does not remove the study data held locally on your device.

05

Encrypted study backup

Backup is off unless you turn it on. When you do, recall assembles a snapshot of part of your study database — your recalls and decks, their review schedules and review history, your focus sessions, your progress and your study plan preferences — and encrypts it on your device with AES-256-GCM before anything is uploaded.

What our servers receive and store is:

• The encrypted snapshot, as ciphertext we cannot read.
• A fingerprint of your encryption key, used to detect whether a recovery key you enter matches the backup. The fingerprint is not the key and cannot be used to derive it.
• The snapshot’s size, format version and last-updated time.

Not everything is included in a backup. User-created problems, individual problem attempts and Feynman explanations are outside the current snapshot format and remain on your device only. Restoring a backup replaces only the backed-up study tables; downloaded content packs are left untouched.

06

recall Pro and payments

recall Pro is sold as an auto-renewing subscription through the Apple App Store and Google Play. Your payment is processed entirely by Apple or Google. We never receive, see or store your card number, billing address or any other payment credential.

To know whether your subscription is active, recall uses RevenueCat, a subscription infrastructure provider, as a processor on our behalf. RevenueCat receives the purchase and renewal events from the stores and tells the application whether the recall Pro entitlement is active. The identifier we give RevenueCat for you is the opaque random identifier of your recall account — never your email address. If you use recall without an account, the identity is anonymous and device-generated.

Your entitlement state — whether Pro is active, and until when — is also recorded against your account on our own server, because access to paid study content is authorised server-side rather than trusted from the application.

07

Downloading study content

recall downloads courses, topics and problems from our hosted content service so that you can study them offline. When your device makes those requests, our hosting provider processes the technical information involved in any internet request — your IP address, the time of the request, and the client making it — as part of delivering the response and protecting the service from abuse. Where you are signed in, the request also carries your account session so the server can check whether you are entitled to the content you asked for.

These requests tell us which content was requested. They do not tell us how you answered anything: your attempts and answers are never sent with them.

08

Crash and error reports

When crash reporting is enabled in a released build, a failure in the application sends us a technical report so that we can fix it. A report contains the error name and message, the stack trace, the component involved, a small amount of technical context such as which operation was running, the recall version, and your platform and operating system version.

Reports are not linked to your account and are not used to identify you. They never contain your answers, notes, explanations or any other study content. If crash reporting is not configured in a build, reports stay in memory on the device and are shown only in the in-app diagnostics view.

09

Study reminders

recall’s reminders are local notifications. They are scheduled by the application on your own device, from your own review schedule, and are delivered by your operating system. There is no push server involved: we do not register a push token for your device, and we do not send you notifications remotely.

On Android, recall requests permission to schedule exact alarms so a reminder arrives at the time you set rather than whenever the system next decides to batch work. You can turn reminders off inside recall, or revoke the notification permission in your operating system settings, at any time.

10

What recall never does

• No advertising, and no advertising identifiers.
• No third-party analytics, attribution, session-replay or tracking SDKs.
• No tracking of you across other apps or websites.
• No sale of personal information, and no sharing of it for advertising.
• No disclosure of your data to data brokers.
• No processing of your notes, answers or explanations by us or by any third-party service, including any machine-learning or AI service. They are not sent anywhere, so they cannot be used to train anything.

We may disclose information where we are legally required to do so — for example in response to a valid legal process — but note that the design above means there is very little to disclose, and that your backup is ciphertext we are unable to decrypt.

11

Service providers

We use a small number of providers to run recall. They act on our instructions and are bound to protect the information they process for us.

12

Retention and deletion

On your device

Local study data is kept until you remove it. You can delete downloaded content per course, remove all downloads, or clear the cache from Settings → Downloads. Uninstalling recall deletes the local database and everything in it.

Your account

You can delete your recall account from inside the application. Deleting it removes your sign-in record, your profile and your encrypted backup from our servers. This is not reversible, and it does not delete the study data on your device.

Your subscription

A store subscription is separate from your recall account and is not cancelled by deleting the account. Cancel it through your Apple or Google account, or through the subscription management screen in recall. We keep a minimal record of subscription events for as long as needed to honour entitlements and to meet tax and accounting obligations.

Diagnostics

Crash reports are retained only as long as they are useful for fixing the failure they describe, and are deleted on a rolling basis.

13

Your rights

Depending on where you live, you have rights over the personal information we hold about you — including under the Nigeria Data Protection Act, the EU and UK GDPR, and comparable laws elsewhere. These typically include the right to:

• Access the personal information we hold about you.
• Have inaccurate information corrected.
• Have your information deleted.
• Receive a copy of your information in a portable form.
• Object to or restrict certain processing.
• Withdraw consent, where processing is based on consent.
• Lodge a complaint with your local data protection authority.

Much of this is built into the application: your study data is already in your possession, account deletion is available in-app, and backup is under your control. For anything else, write to support@numinouslab.com and we will respond within the time your law requires, and in any event within 30 days. We do not sell or share personal information as those terms are defined under California law, and we do not process sensitive personal information for advertising.

14

Children

recall is a study tool for university-level material and is not directed at children under 13. You must be at least 13 years old to create a recall account, or older where your country sets a higher age for consent to data processing — 16 in parts of the European Economic Area. Local study without an account requires no personal information at all.

If you believe a child has created an account with us, contact support@numinouslab.com and we will delete it.

15

Security and international transfers

Traffic between the application and our servers is encrypted in transit. Our database enforces row-level access rules so that account records are readable only by the account that owns them. Your backup is encrypted on your device before upload, and your recovery key is held in your device’s secure keystore. No system is perfectly secure, and we cannot guarantee absolute security, but we design to keep the amount of information worth attacking as small as possible.

Our providers operate infrastructure in several countries, so information may be processed outside your country of residence. Where such a transfer involves personal information protected by your local law, we rely on appropriate safeguards for the transfer.

16

Changes to this policy

If we change this policy we will update the effective date and version at the top of this page. Where a change materially affects how we handle your information, we will give notice in the application before it takes effect. Continuing to use recall after a change takes effect means you accept the updated policy.

17

Contact us

Questions about this policy, or a request about your information, can be sent to support@numinouslab.com. Please tell us which application you are writing about and, if you have an account, the email address you use with it.