This Privacy Policy explains how DZ English Courses (“we”, “us”, “our”) collects and uses your personal data when you use the Development Zenith mobile application, the digital companion to DZ English Courses (the “App”). It also explains your rights under the UK General Data Protection Regulation (UK GDPR) and the Data Protection Act 2018.
This policy covers the App only. Our website (dzenglishcourses.com) and our in-person and online tuition services may be covered by separate notices.
Who we are (data controller)
The data controller for the App is:
- Dagmara Zimnoch, trading as DZ English Courses (sole trader)
- Based in: Peterborough, United Kingdom (full postal address available on request)
- Contact: support@dzenglishcourses.com
The data we collect
When you create an account and use the App, we collect:
- Account details — your email address (required) and, optionally, a display name. Your password is set through our authentication provider and is stored only in a securely hashed form; we never see or store it in plain text.
- Enrolment details (course & corporate students) — if you join a class using a class code, we store your enrolment request and your membership of that class/organisation, including the end date of your course access where your organisation's administrator has set one, and which bespoke course-only content sets (e.g. our idioms, phrasal verbs and language-function material — see “DZ Class Content” in the App) your teacher has made available to your class.
- Content you create — vocabulary “flashcards” you add (the word, its meaning and an example).
- Homework activity (course & corporate students only) — when you submit an assignment, we record that you submitted it and when, together with the score and feedback your teacher gives. Submitting an assignment also adds in-app XP and points to your account, stored on our servers (see “Class standings” below).
Stored only on your device (not collected by us in this version): for every user, your learning progress, completed lessons, daily activity counts, streak count, flashcard review schedule and in-app preferences are saved locally on your device and are not transmitted to our servers. The one exception: when a course or corporate student submits an assignment, that adds in-app XP and points to their account, which are stored on our servers because they feed the teacher's class-progress view and the in-app class leaderboard described below.
Class standings (course & corporate students only): if you are part of a class, other students in the same class can see a leaderboard showing your first name, the initial of your surname, and your total XP. Your own row shows your full name to you; classmates never see your email address, your homework submissions, or any other account details on the leaderboard.
What we do not collect: we do not use analytics or tracking tools, we do not serve advertising, and we do not collect advertising identifiers, your location, your contacts, or camera/microphone data. (The App can play a short celebration sound and use on-device text-to-speech; no audio is recorded or uploaded. It can send you local reminder notifications if you enable them; these are scheduled on your device.)
How and why we use your data (and our lawful basis)
| Purpose | Lawful basis (UK GDPR) |
|---|---|
| Create and operate your account; provide lessons, flashcards and progress features | Performance of a contract (Art. 6(1)(b)) |
| For course/corporate students: deliver assignments and share your submissions, feedback and progress with your teacher/organisation | Performance of a contract (Art. 6(1)(b)) |
| For course/corporate students: show your partially-masked name and XP to classmates on the class leaderboard, and gate access to bespoke course-only content (idioms/phrasal verbs/language functions) per class | Performance of a contract (Art. 6(1)(b)) |
| Keep the App secure and prevent misuse | Our legitimate interests (Art. 6(1)(f)) |
| Send account-related emails (e.g. password reset) | Performance of a contract (Art. 6(1)(b)) |
| Send optional reminder notifications | Your consent (Art. 6(1)(a)) — you can turn these off at any time in Settings or your device settings |
Who we share it with
We do not sell your personal data and we do not share it for advertising. We share it only with:
- Our service providers (processors):
- Supabase (Supabase, Inc.) — database, authentication and file storage. Your account and content data are hosted on Supabase infrastructure located in the European Union.
- Google Play — distributes the App; Google may process limited install and diagnostic data under its own privacy policy.
- Your teacher and organisation — if you are a course or corporate student, the teacher and administrators of the class you join can see your enrolment, your assignment submission status, and your progress within that class. This is a necessary part of the course feature.
- Your classmates (course & corporate students only) — students in the same class as you can see your first name, the initial of your surname and your total XP on the in-app class leaderboard (see section 2). They cannot see your email address, submissions, or any other account details.
- Legal disclosures — where we are required to by law, or to protect our rights, safety, or property.
International transfers
Your data is hosted in the European Union. Where any personal data is transferred outside the UK or the European Economic Area, we rely on an adequacy decision or on appropriate safeguards such as the UK International Data Transfer Agreement / Addendum or Standard Contractual Clauses.
How long we keep it
We keep your account and associated data for as long as your account is active. When you delete your account (see section 8), your data enters a 14-day recovery window — simply sign back in within those 14 days to automatically cancel the deletion and keep your account. After 14 days, your account and its data are permanently removed, except where we are required to retain certain records by law. Content you created that has been anonymised (for example, an assignment retained for another student after a teacher account is deleted) is no longer linked to you.
Your rights
Under UK GDPR you have the right to: access your data; have inaccurate data corrected; have your data erased; restrict or object to processing; data portability; and to withdraw consent (for anything based on consent) at any time. You can get a machine-readable copy of your own data at any time in the App via Settings → Export my data — no need to wait on a request. For anything else, email support@dzenglishcourses.com. We will respond within one month.
You also have the right to complain to the UK Information Commissioner's Office (ICO) at ico.org.uk if you are unhappy with how we handle your data.
Deleting your account
You can request deletion at any time, whether or not you currently have the App installed:
- In the App — Settings → Delete account (type-to-confirm), which signs you out and starts the 14-day recovery window described in section 6; or
- Without the App — via our public account-deletion page or by emailing support@dzenglishcourses.com.
Requesting deletion immediately schedules your account for removal; signing back in within the 14-day window automatically cancels it. Once the window passes, your account and its data (profile, flashcards, homework submissions, class memberships) are permanently removed. If you are a teacher, assignments and other class content you authored are reassigned to a neutral system account rather than deleted, so other students' records remain intact.
How we protect your data
Data is encrypted in transit using HTTPS, passwords are stored only in hashed form by our authentication provider, and access to your data is restricted by row-level security so that users can only reach data they are authorised to see.
Children
The App is intended for adult learners (18 and over) and is not directed at anyone under 18. We do not knowingly collect personal data from children. If you believe a child has provided us with personal data, please contact us and we will delete it.
Changes to this policy
We may update this policy from time to time. We will change the “Last updated” date above and, for significant changes, provide a more prominent notice.
Contact us
Questions about this policy or your data: DZ English Courses — support@dzenglishcourses.com — Peterborough, United Kingdom.