Privacy Policy — MathWrite Notes

Last updated: 6 September 2026

MathWrite Notes ("the app") is an iPad and iPhone app for handwritten notes that can convert your handwriting to LaTeX. This policy describes exactly what the app sends off your device, to whom, and why.

The short version: your notebooks stay on your device. The pages you choose to convert are sent for processing, and we keep an account so you can sign in and so we can count usage. That is all.

1. Who we are

MathWrite Notes is operated by Andrés Osorio Leyenda, Calle Boqueixón Nº 1, 15702 Santiago de Compostela, Spain. Tax ID (NIF): 45907486S. Contact: contact@mathwrite.com.

If you are in the EU or UK, we are the data controller for the processing described below.

2. What stays on your device

Your notebooks, handwriting, page images, scanned documents, imported PDFs and compiled PDFs are stored locally on your device only. They are not uploaded to us, not backed up to our servers, and not associated with your account.

If you delete the app, that content is deleted with it. We cannot recover it, because we never had it.

3. What leaves your device, and when

3.1 Handwriting sent for LaTeX conversion

When a page is converted to LaTeX, an image of that page is sent to our conversion service, which forwards it to Google's Gemini API to produce the LaTeX. The image passes through our server; we do not store it after the request completes.

Conversion happens when you ask for it: creating a new page converts the page you just finished, and the convert action in the editor's menu converts one page on demand. Opening or closing a notebook converts nothing. Pages you never convert are never sent.

Google's handling of that data is governed by the Google AI terms.

3.2 LaTeX sent for compilation

When you compile a document to PDF, the LaTeX source is sent to our service, which forwards it to a LaTeX compiler. The source and the resulting PDF are not retained after the request.

3.3 LaTeX sent to Overleaf

"Open in Overleaf" sends your LaTeX directly from your device to Overleaf. It does not pass through our servers. Once it arrives, it is held under Overleaf's own privacy policy. The app keeps Overleaf's cookies so you stay signed in to your Overleaf account between sessions.

3.4 Your account

Signing up stores your email address with Supabase, our authentication provider. If you sign in with Google, we receive your email address and basic profile information from Google; we do not receive your Google password.

Your notebooks are not linked to this account. The account exists so you can sign in and so usage can be counted against it.

3.5 Usage counts

We store, against your account, how many conversions and compilations you have used. There are two counts and they exist for different reasons: one covers the current month and enforces a subscriber's fair-use limit; the other is a running total that never resets and is what tracks a free account's one-off allowance. We do not store what you converted, only how many times.

3.6 Subscription and analytics

We use Superwall to show subscription options and RevenueCat to process the purchase and record whether a subscription is active. RevenueCat receives your account identifier and details of the subscription itself. Superwall receives technical information about your device and app — model, OS version, language, region, time zone, app version, an anonymous device identifier, and an approximate location derived from your IP address (typically city and country level). It also records paywall and purchase events.

The app does not use the advertising identifier (IDFA) and does not include ad tracking frameworks.

3.7 Payments

Subscriptions are purchased through Apple. Apple processes the payment; the app never sees or receives your payment details.

4. Legal bases (EU/UK)

  • Contract — your account, subscription status and usage counts: we cannot provide

    • the service without them.

  • Contract — conversion and compilation: these are the features you asked for.
  • Legitimate interests — basic device and paywall analytics, to keep the app

    • working and understand which offers people see.

    5. How long we keep things

  • Account data: until you delete your account.
  • Monthly usage counts: for the current and previous billing periods.
  • The free allowance count: for as long as the account exists, because it is granted

    • once and we would otherwise have no way to tell it had been used. Deleting your account deletes it.

  • Page images and LaTeX sent for processing: not retained after the request

    • completes.

  • Subscription records: for as long as required for accounting and tax.

    • 6. Your rights

    If you are in the EU or UK, you may request access to, correction of, deletion of, or a copy of your personal data, and you may object to processing based on legitimate interests. Write to contact@mathwrite.com.

    You can delete your account from Settings → Account → Delete account. This removes your account and its usage records. It does not delete your notebooks, because those were never ours — they are on your device, and you delete them by deleting them in the app or removing the app.

    You also have the right to complain to your local data protection authority. In Spain that is the AEPD.

    7. Children

    The app is not directed at children under 13, and we do not knowingly collect their personal data.

    8. International transfers

    Our providers — Supabase, Google, Superwall, RevenueCat, Vercel — may process data outside the European Economic Area, including in the United States. Where that happens, transfers rely on the European Commission's Standard Contractual Clauses or an adequacy decision.

    9. Changes

    If this policy changes materially we will update the date at the top and, where the change is significant, tell you in the app.

    10. Contact

    contact@mathwrite.com