Privacy Policy

Effective 20 October 2026

Who we are

Marker Lab (the app for iPhone, iPad and Mac, and this website, markerlab.app) is made by Dmytro Nikolaienko, an individual entrepreneur registered in Ukraine. He is the controller of the personal data described here. In this policy “we” and “us” mean him.

Contact for anything about privacy: support@markerlab.app.

What stays on your device

These are stored only on your device and are never sent to us:

• photos of your paintings in the sketchbook, and the photos you use for A Lesson from Your Photo;
• the name in a profile (optional, for adults and for children), and your marker set, including a photo of your marker box: the numbers on the caps are read on the device;
• lessons you built from your photos, saved tips from the teacher, your garden, settings and the parent PIN (kept in the device Keychain). Face ID or Touch ID, used to reset the PIN, is handled by your device: we never see it.

Without signing in, your learning progress also stays on the device. Your device may include app data in its own backups (for example iCloud Backup), under your Apple settings.

Sign in with Apple and sync

Signing in is optional. It lets a grown-up see the same progress on iPhone, iPad and Mac, and restore it after reinstalling the app. If a child paints, a grown-up should sign in.

What we receive and keep when you sign in:

• the identifier Apple creates for Marker Lab (it is unique to our app and is not your Apple ID email);
• the app’s region and language setting (for example “uk_UA”), the dates the account was created and last used;
• a token from Apple, stored encrypted, used only to revoke Sign in with Apple when you delete your account;
• a sign-in session, stored only as a keyed hash. Sessions expire after 90 days.

We request no name and no email address from Apple, so Apple does not share them with us.

What syncs while you are signed in:

• learning progress per lesson: the lesson, the step reached, minutes spent, when it was completed and last changed;
• a record of each work in the sketchbook: which lesson, the date and a random ID. The photo itself is never uploaded;
• who paints: “adult” or “child” and, for a child, the age band you chose (6-7, 8-9, 10-11, 12-13 or 14+). Never the name;
• if we gave the account free access (for example to a teacher or a partner), a short note about it.

Why: to provide the sync you asked for (performance of our agreement with you).

Usage statistics and error reports

The app sends first-party usage statistics to our own server. We use them to see where lessons are hard, which steps people skip and what breaks, so we can make the course better. No third-party analytics service receives them.

What is sent:

• a random install ID created by the app on first launch (it is not a device or advertising identifier, and a reinstall creates a new one);
• events from a fixed list, such as “lesson opened”, “step completed”, “print sheet opened” or “purchase screen shown”, with values from fixed lists only: there is no free text;
• context: platform, app version, operating system major version, app language, region format, time zone offset, how the app was installed (App Store, TestFlight), the access level, and the profile type and age band;
• error reports: an error code and the area it happened in (for example “sync” or “camera”), never the content you work with.

Our server adds the country of the connection (for example “UA”) and does not store the IP address. Names, photos, typed text, email addresses, device models and advertising identifiers are never sent.

If a grown-up signs in, the statistics of that install are linked to the account. After signing out, new events are sent without the account.

Your choice: For Parents › Usage statistics. Turning it off stops recording, deletes what is waiting on the device and erases what our server stored for this install. When you turn it on again, the app starts with a new install ID.

Why: our legitimate interest in improving and fixing the course, with the switch above to object at any time.

Purchases

Purchases and subscriptions are made through Apple. Apple handles payment, and we never see your card or payment details.

Apple sends our server App Store Server Notifications about transactions: the product, price and currency, the App Store country, dates, transaction IDs, whether it is a trial, a renewal or a refund, and whether it came through Family Sharing. If you are signed in, the app tells Apple to attach the purchase to your account, so we can link it.

To decide whether a device may use the paid limits of the AI features without signing in, the app sends the signed App Store transaction. Our server checks Apple’s signature and keeps only keyed hashes: of the check result for up to 6 hours, and of the transaction and the install for up to 3 days, to limit how many devices one purchase can unlock.

Why: to provide what you bought, and to meet our accounting and tax obligations.

Invite codes and partner links

If you open a partner link, our server counts the click by the code and the time only, without your IP address or device details. If you enter an invite code in the app, it is saved with your account when a grown-up signs in (within 7 days of creating the account and before any purchase), so we can pay the partner their share.

AI features

Marker Lab has two optional features that use AI: Teacher’s Tip (feedback on a photo of your painting) and A Lesson from Your Photo (a step plan for a lesson made from your own photo). The tips are written by Claude, an AI model made by Anthropic.

Only when you ask. Nothing is sent until you tap to send. Before the first request the app shows who will look at it and asks you to confirm. On a child’s profile a grown-up confirms this once through the parental gate, and parents can require the PIN for these features. Each feature can be switched off in For Parents.

What is sent for Teacher’s Tip: the photo of the paper sheet, cropped to the sheet and re-encoded without location or other metadata; the target picture of that step; the lesson and step; the numbers and colour names of your markers; the app language; and the profile type and age band. Before sending, the device checks the photo, and if it sees a face or a person, it asks you to photograph only the sheet.

What is sent for A Lesson from Your Photo: the photo stays on your device. The device turns it into zones in your marker colours, and only a simplified colour map (with any faces filled as flat colour) and a summary of the zones in numbers are sent, together with your marker labels, the language, and the profile type and age band. Without the internet, the app builds the plan on the device instead.

Where it goes. Our server checks the request and passes it to Anthropic’s API, which writes the answer, and our server sends the answer back to your device, where it is saved with your work.

• We do not store the photo or the colour map. They are passed to Anthropic and dropped when the request ends.
• The answer text is kept on our server for up to 10 minutes, so that a retry of the same request gets the same answer, and is then deleted.
• For 90 days we keep technical records of each request without any user or install ID: the feature, lesson and step, language, outcome, timing, the model and the amount of text processed.
• To apply daily limits we keep a keyed hash of the install ID and of the network address for up to 3 days (the time zone used for the daily limit, up to 30 days). We never store the IP address itself.

Anthropic. Anthropic processes this data for us under its commercial terms. Under those terms Anthropic does not use it to train its models. Anthropic’s policy is to delete API inputs and outputs within 30 days, unless it needs to keep them longer to enforce its usage policy or to comply with the law. Read more in Anthropic’s Privacy Center.

Why: to give you the answer you asked for (performance of our agreement with you, and your consent where the law requires it, which you can withdraw by switching the feature off).

Support email, security, this website

Support email. If you write to us, we receive your email address and your message and use them only to answer you.

Protection from abuse. To limit how often the server can be called, it keeps a keyed hash of the network address for about 48 hours at most. The IP address itself is not stored, and our server logs do not record the content of requests.

This website. markerlab.app uses no cookies, no analytics and no tracking scripts. Our hosting provider, Cloudflare, processes technical data such as IP addresses to deliver the pages and protect them from attacks.

What we don’t do

• No advertising, and no advertising identifiers.
• No selling or renting of personal data.
• No third-party analytics or advertising SDKs in the app.
• No tracking across other companies’ apps or websites.
• No access to your location, contacts or microphone. “Read to me” uses the speech voices built into your device.

Who helps us

• Cloudflare hosts our server, its database and this website.
• Anthropic writes the answers of the AI features, only for requests you send.
• Apple provides Sign in with Apple and handles App Store purchases, under Apple’s own privacy policy.
• Our email provider delivers support email.

These providers may process data outside Ukraine and the European Economic Area, including in the United States. We rely on their data protection terms for these transfers.

How long we keep data

Deleting your data

Delete the account in the app: For Parents › Sync › Delete account. Apple asks you to confirm it’s you. We then delete:

• synced progress, sketchbook records, the profile type and age band, the language setting and all sign-in sessions;
• the usage statistics of every install that was ever signed in to this account;
• notes about free access.

The account record becomes an anonymous placeholder, and we revoke Sign in with Apple for Marker Lab. Purchase records stay for accounting, no longer linked to you. Data on your device (progress, garden, photos) stays until you delete the app. Deleting the account does not cancel an App Store subscription: cancel it in your Apple account settings under Subscriptions.

If you stop using Sign in with Apple for Marker Lab in your Apple account settings, Apple tells us and we end all sign-in sessions. If you delete your Apple Account, Apple tells us and we delete the Marker Lab account in the same way as above.

Without an account: turn off Usage statistics in For Parents to erase what our server holds for the install, or delete the app. You can also write to us.

Your rights

Depending on where you live, including under the Law of Ukraine “On Personal Data Protection” and the EU General Data Protection Regulation, you have the right to:

• know what we hold about you and get a copy;
• correct it or have it deleted;
• restrict or object to processing, including the usage statistics;
• receive data you gave us in a portable format;
• withdraw consent at any time, without affecting earlier processing;
• complain to a data protection authority. In Ukraine this is the Ukrainian Parliament Commissioner for Human Rights; in the EU, the authority in your country.

Write to support@markerlab.app. We answer within one month. Because we don’t know your name or email, we may ask for details that let us find your records, for example to send the request from the app’s settings or to confirm a recent purchase.

Children

Marker Lab is made for families, and children often paint with it. It is designed with parents in mind:

• children don’t need an account. If a child paints, a grown-up signs in;
• a child’s name stays on the device; only the age band can sync;
• there is no advertising, no third-party analytics and no chat. A child cannot type anything to the AI;
• purchases, links out of the app, sharing and For Parents are behind a parental gate: the parent PIN, or a short check that a grown-up is there;
• the AI features need a grown-up’s confirmation once on a child’s profile and can be switched off.

If you believe a child has given us personal data without a parent’s permission, write to us and we will delete it.

Security

All connections use HTTPS. Sign-in sessions are stored only as keyed hashes and Apple tokens are encrypted. We collect as little as we can, and only the developer has access to the server data. No system is perfectly secure, but we work to keep your data safe and will tell you and the authorities about a breach where the law requires it.

Changes and contact

When we change this policy, we update the date at the top of this page. If a change affects how we use data you have already given us, we will ask for your consent where the law requires it.

Questions, requests or complaints: support@markerlab.app. Dmytro Nikolaienko, individual entrepreneur, Ukraine.