Privacy Policy

Last updated: November 12, 2026

Who we are

Halley is developed by Henrique Augusto de Mello, the controller of the data described in this policy. Contact: contact@hmello.com

What stays on your device

Your decks, cards, review history, statistics, reminders and widget data are stored on your iPhone. They are not sent to us.

Account

When you first open the app, we create an anonymous session so it can work. If you sign in with Google or Apple, we receive an account identifier and the email address provided by that service (with Apple, this may be a relay address). We use this to identify your account, apply the monthly generation limit and link your purchases.

AI card generation

When you generate cards, the content you submit is sent to our server and to Google's Gemini API, which creates the cards. That content can be pasted text, text extracted on your device from a PDF or from a YouTube video's captions, or a photo. The PDF file and the video itself never leave your device.

We do not keep the content after the cards are generated. We only keep how many generations you used each month. Google processes the content under the Gemini API terms.

Purchases

Payments are processed by Apple. We never have access to your payment details. We use RevenueCat to manage the subscription and packs: it receives your account identifier and your App Store purchase history. We store your subscription status (plan and expiry) and your balance of extra generations.

Usage data

We use PostHog, with servers in the European Union, to understand how the app is used: screens visited, feature use and technical information about your device and the app. After you sign in, these events are linked to your account identifier. You can turn this off at any time in Account → Share usage data.

Where your data is stored

Our server (Supabase) is located in the European Union. Google, RevenueCat and Apple may process data outside the EU. In those cases, transfers are protected by standard contractual clauses or equivalent safeguards.

Legal bases

We process data to provide the service you ask for (account, AI generation and purchases), to meet legal obligations, and, for usage data, on the basis of our legitimate interest in improving the app. You can object to the latter by turning it off.

How long we keep data

We keep account data for as long as the account exists. Generation counts are recorded per month. Usage data is kept for as long as needed for analysis and then deleted or anonymized.

Your rights

You can delete your account at any time in the app, under Account → Delete account. This erases the account, your balance of extra generations and your usage count; your decks stay on your device. Deleting the account does not cancel a subscription: do that in your Apple account settings.

You can also ask to access, correct, delete or port your data, and object to processing based on legitimate interest, by writing to contact@hmello.com. You can also lodge a complaint with the data protection authority in your country.

Children

Halley is not directed to children under 13, and we do not knowingly collect data from children.

Changes to this policy

We may update this policy. Important changes will be announced in the app.