Privacy policy

Last updated September 22, 2026

Eigenboard is a notebook app for iPad and iPhone that turns handwritten pages into LaTeX documents. This policy explains what we collect, why, and what we never do with it.

What stays on your device

Your ink, your notebooks, page thumbnails, imported PDFs and photos, and the LaTeX and PDFs the app produces are stored on your device. They are not synced to our servers and we cannot see them.

What we process to convert a page

Pages you choose to convert are sent to our server, which uses a third-party AI service to produce the LaTeX. Along with the page image, the app sends the LaTeX of the previous page (so a proof can continue across pages) and the subjects you chose during onboarding. The image is processed for that request only and is not kept by us afterwards. When you compile, the assembled LaTeX document is sent to our compile service and the PDF is returned. We keep a record that a conversion or compile happened (time, size, whether it succeeded) for billing and abuse prevention. Your notebooks, handwriting and PDFs otherwise stay on your device.

Your account

To use the app you sign in with Apple, Google or an email address and password. We store your email address, your sign-in method, the role and subjects you chose during onboarding, and your subscription status. Authentication is provided by Supabase.

Subscriptions

Purchases are made through the App Store. Apple handles payment; we never see your card details. We use RevenueCat to check whether your subscription is active. RevenueCat receives an anonymous identifier for your account and your purchase history from Apple.

Waitlist

If you join the waitlist on this site we store the email address you enter and the platform you chose. We use it only to tell you when that version is available. Unsubscribe by replying to any email we send.

What we do not do

• We do not sell personal data.
• We do not use your handwriting or notes to train models.
• We do not show advertising in the app.

Service providers

Supabase (authentication and database), Vercel (hosting), a third-party AI service (transcription), RevenueCat (subscription status) and Resend (transactional email). Each processes data only to provide its service to us.

Deleting your account

Open the account screen in the app and choose Delete account. This removes your account, profile, subscription record and usage history from our systems immediately. Notebooks on your device are deleted at the same time. To cancel a subscription, use your Apple ID subscription settings.

Children

Eigenboard is not directed at children under 13 and we do not knowingly collect data from them.

Changes and contact

If this policy changes in a way that matters, we will note it here with a new date. Questions go to support@eigenboard.com.