Privacy Policy

Last updated 2 August 2026

This policy explains what that means in practice, and it is short because there is very little to describe. It applies to the Crest iOS app and to this website.

What we collect

Nothing. Crest does not ask for your name, email address, phone number or date of birth, and it has no way to identify you. The app contains no analytics, no advertising code, no tracking identifiers and no third-party software development kits of any kind.

Because nothing is collected, there is nothing for us to sell, share, disclose or lose in a breach.

What stays on your device

Everything you put into Crest is stored locally on your iPhone using Apple's standard on-device database, protected by your device passcode and Apple's file encryption. That includes:

• The documents and notes you import, and the concepts drawn from them
• Your exams and their dates
• Your review history, streak and readiness figures
• Your reminder preferences

If you delete the app, all of it is deleted with it.

iCloud backup

So that changing or losing a phone does not cost you a term's work, Crest stores that data in your own private iCloud database, using Apple's built-in sync. This is the same mechanism Apple's own apps use, and it means:

• The data belongs to your Apple Account, not to us. We cannot read it — we have no access of any kind to your iCloud data.
• Apple cannot read the contents of a private database either; it stores encrypted records on your behalf.
• It syncs to your other devices signed into the same Apple Account, and to nowhere else.
• You can switch it off at any time in Settings › your name › iCloud, and Crest keeps working entirely on the device.

Your progress and your schedule go nowhere else, and even here they go to storage only you control.

How your material is read

Turning a PDF or a page of notes into good questions needs a language model. Earlier versions of Crest used the one built into recent iPhones, which kept everything on the device — but most phones cannot run it, and the result was that the app worked well for some people and poorly for others with no way to tell which you would be. Crest now uses one model for everyone, and it runs on a server.

What is sent, each time you import material:

• The text of the material, a section at a time.
• Which language it is written in, and how many questions to draw from each section.

What is not sent: your name, your email, any account or device identifier, your exam dates, your progress, or anything else from the app. There is no identifier to send — Crest has never had one. The requests cannot be linked to each other or to you.

What happens to it:

• Our server passes the text to DeepSeek, which reads it and returns the questions.
• We do not store your material. On our server it exists in memory for the seconds the request takes and is gone when the response is returned.
• DeepSeek may. Its published privacy policy states that data it receives is stored on servers in the People's Republic of China, that inputs may be retained and used to improve its models, and it does not state a retention period. We have no arrangement with DeepSeek that changes this, and we cannot delete anything on your behalf once it has been sent.
• Our logs record the size of each request and how many questions came back. They never contain the text.
• Processing therefore happens outside Argentina and outside the EU, in a country that neither has recognised as offering an equivalent level of data protection. Importing material is optional and the app tells you this before you do it; choosing to import is how you consent to that transfer.
• Your device's IP address reaches our server, as it does with any request to any website. It is used to stop one caller flooding the service and it appears in our host's standard logs for a short period. It is not attached to your material and not used to build a profile.

If your phone has no connection, or once a free account has used its free documents, Crest reads your notes on the device instead — the structure of lines written as "term: definition", or Apple's on-device model if your iPhone supports it. In those cases nothing is sent anywhere at all, and the app tells you which is happening before you import.

If you would rather nothing left your phone, do not import material you would not want read. Notes typed or pasted as "term: definition" are handled entirely on the device and are never sent, and every other part of Crest — the sessions, the schedule, the readiness figure — works exactly the same either way.

Either way, the questions Crest writes come only from the material you gave it. It does not add facts of its own.

Purchases

Crest offers optional paid subscriptions. Payment is handled entirely by Apple through the App Store. We never see and never receive your card details, billing address or Apple Account information. The app asks Apple only whether an active subscription exists, and that answer stays on your device.

Apple provides us with aggregate, anonymised sales reports — totals such as how many subscriptions were sold in a country. These cannot be linked to any individual. Apple's own handling of your purchase is governed by Apple's Privacy Policy.

Notifications

Reminders are optional and off until you turn them on. They are scheduled by your iPhone itself and their content is generated on the device. No notification is ever sent from a server, and nothing about your schedule is sent anywhere in order to produce one.

Your data, and deleting it

We hold no data about you. Material sent to be read is not kept once the questions come back, so there is nothing for us to export or erase on your behalf. You remain in full control of everything on your device:

• Delete a single exam, along with all its material and progress, by swiping it away in the app
• Remove all material from an exam, or reset your progress, from the exam's options menu
• Delete everything at once by deleting the app from your iPhone

If you are in a region with rights under the GDPR, the CCPA or a similar law — such as the right to access, correct, port or erase your personal data — those rights are satisfied by the fact that we hold none of it.

Children

Crest is not directed at children under 13, and because it collects no personal data it does not knowingly collect anything from anyone of any age.

This website

This site sets no cookies, runs no analytics and embeds no third-party scripts or fonts. Our hosting provider, Vercel, may keep standard server logs — IP addresses and requested pages — for a short period for security and reliability. The same applies to the requests the app makes when it reads your material. We do not use those logs to build a profile of anyone.

Changes

If this policy changes in a way that affects you, the date at the top will change and the updated version will be published here before the change takes effect in the app.

Contact

Questions about this policy can go to tomas.federico2107@gmail.com.