NABLA LEGAL
Privacy Policy
Nabla is designed to work without an account. You never give us your name, email address, or phone number to use the app. This policy explains what the Nabla mobile application handles, and what it does not.
Information stored on your device
Nabla stores your learning progress, completed skills, XP, streaks, hearts, achievements, review scheduling, exam results, onboarding state, and app preferences locally on your device. This information stays on your device and is not uploaded to a Nabla server.
No account, no profile
Nabla does not operate a user account system. We do not ask for, collect, or store your name, email address, phone number, contacts, photos, precise location, or any other directly identifying personal information. We do not sell personal information, and we do not share it with data brokers or advertisers.
Anonymous usage analytics
To understand which lessons work and where learners get stuck, Nabla records anonymous product events such as installing, opening and closing the app, moving between screens, starting and completing a lesson, mastering a skill, running out of hearts, viewing the upgrade screen, and starting or completing an exam. These events include the platform (iOS or Android), your app version, and basic details about the lesson or screen involved — for example the identifier of the skill, never anything you wrote.
Screens are recorded by their route name, such as lesson/[skillId], so the record is which kind of screen you were on rather than a trail of individual pages.
Each installation is given a randomly generated identifier — a UUID such as 018f2c6a-4b1e-7c3d-9a52-6f0e1d7b2c84 — that is created on your device and is not derived from your device's hardware identifiers, advertising ID, or any personal information. It cannot be used to identify you, and it is not linked to a name, email address, or account.
This data is processed on our behalf by PostHog, hosted in the European Union. It is used only to improve Nabla, is not used for advertising, and is not sold. The separate, much smaller set of events used to measure our own advertising is described under “Advertising and how we measure it” below.
Session recording
Nabla also records an anonymous replay of your session — the screens you move between and where you tap — so we can see where a lesson becomes confusing instead of guessing from numbers alone. These recordings carry the same anonymous installation identifier described above and no personal information.
Anything you type is masked before the recording leaves your device, so your input is never legible in a replay. Recordings are processed by PostHog and stored in the European Union, are used only to improve the app, and are never used for advertising or sold.
Subscriptions and payments
Nabla Pro is an auto-renewing subscription sold through the Apple App Store or Google Play. Nabla never sees or stores your payment card, billing address, or store account credentials. Apple or Google processes the transaction under their own privacy policies.
We use RevenueCat to tell the app whether your subscription is currently active. For this purpose the app sends and receives subscription status information, such as which product was purchased, whether a trial is running, and when the current period ends, associated with an anonymous purchase identifier rather than your identity.
Advertising and how we measure it
Nabla shows no advertising inside the app. There is no ad network placing banners or videos in front of you, and nothing you see in Nabla is paid placement.
We do advertise Nabla elsewhere — on Meta (Facebook and Instagram) and on Google — and to know whether those ads bring people who actually use the app, a small set of events is sent to those two companies: completing onboarding, finishing a lesson, mastering a skill, opening the upgrade screen, starting a purchase, and completing a purchase, with the amount and currency for the last two. This is done through Meta App Events and Google Analytics for Firebase. Nothing you type, and none of your progress data, is included.
On iOS this uses your device's advertising identifier only if you allow it. The system asks once, with the App Tracking Transparency prompt; if you decline, no advertising identifier is collected and nothing is sent to Meta. Google Analytics for Firebase still receives the events listed above, without any advertising identifier and with ad personalization switched off, so Google can count installs and purchases in aggregate. On Android, your system-level advertising ID setting is respected. You can change either choice at any time in your device settings.
Meta and Google process this data under their own privacy policies. It is used to measure and improve our own advertising, and it is not sold.
Sharing a progress card
If you choose to share a progress card, Nabla creates the image on your device and opens your operating system's share sheet. Nabla does not control the third-party app or service you select, and that service's privacy policy will apply.
Study reminders
If you turn on reminders, Nabla schedules them on your device using your operating system's local notifications. They are not sent from a server, and Nabla does not use push tokens. You can turn them off in the app's settings or in your device settings at any time.
Update checks
When it opens, Nabla downloads a small public file from this website that lists the oldest app version still supported and the newest one available, so it can tell you when an update is ready or required. The request carries no identifier or progress data; like any web request, it reveals your device's IP address to the website host (GitHub Pages). On iPhone, if that file does not include the App Store link, tapping Update may also ask Apple's public App Store lookup for Nabla's listing.
Device and store services
The Apple App Store, Google Play, your device manufacturer, and your operating system may process technical, diagnostic, crash, purchase, or distribution information under their own privacy policies. Nabla does not receive this information except as described above.
Children
Nabla is a general-audience education app built for university-level mathematics and is not directed to children under 13. We do not knowingly collect personal information from children. If you believe a child has provided us with personal information, contact us and we will delete it.
Your choices and data deletion
Because your progress is stored locally and no Nabla account exists, you can delete Nabla's stored data at any time by using the reset option in the app settings, clearing the app's storage in your device settings, or uninstalling the app. Uninstalling also discards the anonymous analytics identifier — a fresh install generates a new one, and past session recordings lose their link to your device with it.
To request deletion of previously collected anonymous analytics events and recordings, contact us at the address below with the approximate dates and the device you used, and we will delete the records we can identify from that.
Your rights
Depending on where you live, you may have rights to access, correct, delete, or restrict processing of personal information, or to lodge a complaint with your local data protection authority. Nabla holds no directly identifying information about you, but you can exercise these rights regarding the anonymous data described above by contacting us.
Changes to this policy
If Nabla later adds accounts, cloud sync, advertising, or other data processing, this policy and the relevant store disclosures will be updated before those features are released, and the effective date above will change.
Session recording, and advertising measurement through Meta and Google, are described above and were added on September 3, 2026.
Contact
For privacy questions or requests, email hamzacakmak833@gmail.com or use the Nabla support page.