Privacy

Last updated: 10 October 2026

Who we are

Zelinx Study Planner is made by Zelinx ("we", "us"). If you have a question about your data, or want us to do something with it, email devpiruspoker@gmail.com.

Using the app without an account

Your plan, progress, cards, notes and settings are saved on your own device and nowhere else. A profile PIN only protects a profile on that device; it never leaves it.

What we store if you sign in

Signing in is optional. You sign in with Google, and the app keeps your study data in step on every device where you sign in. To do that, we store:

From your Google account

Your Google account's ID number, your email address, your name and the link to your profile picture. That's all we ask Google for. We never see your Google password, and we can't read your Gmail, Drive, contacts or anything else in your Google account.

Your study data

What you choose to sync by signing in: your progress (ticked topics, test and paper scores, flashcards, mind maps, mistakes, notes, essays and answers you typed), your plan (subjects, topics and term dates) and a few preferences (theme, subject colour, typed answers on or off, reading speed, how papers and subjects are shown). If you star or tag an email or a Teams assignment in the app, the copy the app keeps of it is part of your progress, so it's synced too.

Your signed-in devices

For each device you sign in on: a label like "Linked device (Windows desktop)", when it signed in, when it was last used and when the sign-in runs out. The secret key each device uses is stored only in a scrambled form (a one-way hash) that can't be turned back into the key.

Sign-in codes

When you sign in the desktop or Android app, the 8-character code and the device's name, for at most 10 minutes.

Protection against abuse

To stop anyone flooding the service, we count requests from each internet connection for a short time. We never store your IP address itself, only a scrambled, shortened code made from it (a keyed hash), and the counts are deleted after about a day.

Housekeeping

When your account was created and last signed in, and how much space your data takes up.

How much free AI marking you used

If you use the free AI marking, essay coach or subject drafting, how many of each you used each day and how much text that was for the AI (counted in "tokens"), so we can keep to the daily allowance and our budget. Never the questions, answers, essays or specifications themselves.

What we don't store or do

• No passwords: there aren't any. Google handles signing in.
• No profile PINs. They stay on your device.
• No API keys. Your Anthropic API key stays on your device; it is never synced, and the server throws away anything in your preferences that looks like a key, password or token.
• No Outlook settings, and nothing from Outlook or Teams unless you star or tag it (see above).
• Nothing you send to the AI. Your answers, essays and specifications pass through our server to Anthropic and back, and are not kept or logged.
• No ads, no selling or renting your data, no analytics, no tracking cookies.

Where it's kept

On servers run by Cloudflare, Inc., in a Cloudflare database. Cloudflare stores and processes the data for us and isn't allowed to use it for anything else. Its servers may be outside the UK. Cloudflare keeps restore points of the database for up to 30 days, so anything deleted is fully gone from them within 30 days.

Data travels between your devices and the server encrypted (HTTPS). Each signed-in device holds its own secret key in the app's private storage on that device; the app never puts it in its backups or profile exports.

How long we keep it

• Your account and study data: until you delete your account.
• A device's sign-in: until you log out, or 180 days after it was last used.
• Sign-in codes: 10 minutes. Abuse counters: about a day. AI marking counts: 90 days.

Downloading or deleting your data

• Download my data (Settings → Account) gives you one file with everything we store about your account.
• Log out stops syncing on that device. Log out everywhere signs out every device at once, if you've lost one or signed in on someone else's.
• Delete my account (Settings → Account) deletes your account and everything stored for it straight away: your details, your synced data and every device's sign-in. It doesn't touch the copy on your devices, which keep working without an account. You can't undo it; signing in again later starts a new, empty account.
• You can also email us to see, correct or delete your data. If you're in the UK and unhappy with how we handle it, you can complain to the Information Commissioner's Office at ico.org.uk.

Children

Accounts are for people aged 13 and over. If you're under 13, please don't sign in: you can use everything in the app without an account. If you think a child under 13 has made an account, email us and we'll delete it.

Some school Google accounts can't sign in to apps their school hasn't approved. If yours is refused, you can use a personal Google account, or ask your school to allow the app.

Other parts of the app that use the internet

• AI marking, the essay coach and subject drafting use Claude, made by Anthropic. Only when you press the button, the question, its mark scheme and your typed answer (or your essay, or the specification you're drafting from) are sent to Anthropic to be marked: through our server if you're signed in, where they are passed on and not kept, or straight from your device if you've added your own Anthropic API key. Nothing about you goes with them, not even your name. Anthropic handles them under its commercial terms, which don't let it train its models on them, and its privacy policy applies.
• Lesson videos and their preview pictures come from YouTube (youtube-nocookie.com), and YouTube's privacy policy applies to them.
• Updates: the desktop and Android apps check for new versions by downloading a small file from this website (the desktop app tries GitHub if this site can't be reached).
• Read-aloud: the first time you press Listen, the desktop app downloads the narrator from this website (or GitHub) and each voice you pick from Hugging Face.

Changes to this page

If we change what we store or how we use it, we'll update this page and the date at the top before the change happens.