Privacy policy

Compasswork (Zirkelwerk) · As of October 2026

1. Controller

The controller within the meaning of Art. 4 No. 7 GDPR is:

No data protection officer has been appointed, as the requirements of Art. 37 GDPR and § 38 BDSG are not met.

2. Principle: no data collection

Compasswork does not process any personal data on the provider's servers. The app works entirely offline. There are no user accounts, no registration, no analytics or tracking services, no advertising and no sharing of data with third parties.

3. Data stored on the device

Everything you create in the app stays exclusively on your device. The following is stored:

• your sheets: name, folder, drawings (lines, arcs, freehand strokes, points and texts), pictures you have placed on a sheet yourself (reduced in size), the last view, the position of the drawing instruments, a small preview image and, where applicable, a task that has been set (type of task and given parts or starting figure) and the highest help level used
• your settings, such as language, appearance, paper type, colour and line width, toolbar position, pencil behaviour and any screen size calibration
• the first name or initials entered for results sent to a teacher
• on a teacher's device: collected submissions (name or initials, task, result of the check, detected errors, help level used and – if included in the code – the drawing)
• whether you have already drawn with a stylus, so that fingers only move things afterwards and do not draw by accident
• the date of the last backup of all sheets (for the reminder in “My sheets”)

Sheets are stored using the browser technology IndexedDB and settings using localStorage, both in the protected app directory. They are never transmitted. Uninstalling the app removes them completely. Individual sheets can be deleted in the app under “My sheets”.

Texts you write on a sheet and pictures you insert are, like all other content, stored locally only. Please do not write or place names or other personal details of students on sheets you intend to share. If you photograph pages of textbooks, please follow your school's copyright rules for copying and sharing.

4. Export, import, PDF and QR codes

Exporting creates a file (extension .zirkelwerk) and passes it to your device's share function. Where the file goes from there (e.g. the Files app, AirDrop or email) is entirely up to you. When importing, you choose a file yourself; the app reads only that file.

“Back up all sheets” creates, in the same way, a single file with all sheets (including pictures and folders) and all submissions. Where you keep the backup (e.g. iCloud Drive or a USB stick) is entirely up to you. When restoring, the app reads only the chosen file and adds missing sheets on the device.

Pictures placed on a sheet are included in exported files, backups and PDFs. They are not included in QR codes.

A PDF of a sheet and a video of the playback are likewise created on the device only and passed to the share function (e.g. for printing or a learning platform).

“Read aloud” uses the device's speech output (on the iPad that of iOS). Compasswork only passes the text of the construction steps to the operating system and stores nothing.

A task QR code contains only the task itself: for lab tasks the congruence condition and the given parts, for a shared sheet its name and drawing. It is created in the app and shown on screen. Compasswork does not access the camera for this: the device's camera app scans the code and hands the link to Compasswork. The app checks the content and creates a sheet on the device from it; nothing is transmitted.

A result for the teacher is also a QR code that is only shown on screen. It contains the task, the result of the automatic check, the detected errors, the help level used, the first name or initials entered and – if the code is large enough – the student's own drawing. When the teacher scans the code, Compasswork stores this information on the teacher's device only. It can be deleted at any time under “My sheets → Submissions”. Please use first names or initials only.

5. Permissions

The app does not request access to the microphone, contacts or location.

Inserting pictures: “Insert picture” opens the system's picker. Compasswork only receives the one photo or file you choose there – the app has no access to the rest of your photo library. If you take a new photo with “Take Photo”, the system asks once for permission to use the camera; the camera is used only at that moment and only when you ask for it. The photo is stored on the sheet in reduced size and is not transmitted.

The device's share function may offer to save an image to the photo library; the system may ask for your permission to do so.

6. Internet connections

The app does not establish any network connections on its own. It contains no external libraries, no fonts from third-party servers and no embedded content.

7. In-app purchase

If you purchase the full version, the purchase is handled entirely by Apple's App Store or Google Play. The provider of this app does not receive any payment details. The app only learns from the store whether the full version is unlocked for your account and remembers this on the device so that it also works offline. Apple's or Google's privacy policies apply.

8. Distribution via an app store

When you download the app from an app store, its operator processes data on its own responsibility (such as account, device and time of download). The provider of this app has no influence on this. The privacy policy of the respective operator applies.

9. Your rights

You have the right of access, rectification, erasure, restriction of processing, data portability and objection under Art. 15 to 21 GDPR, as well as the right to lodge a complaint with a supervisory authority. As the provider does not store any personal data, requests for access or erasure addressed to the provider will generally have no effect. You can delete all data yourself in the app at any time.

10. Changes to this policy

This policy will be updated whenever app features relevant to data protection change. The current version is available in the app and on this page.

11. Contact

For questions about data protection, please contact smaehlmann.appdev@gmail.com.

This English version is provided for convenience; the German version is legally binding.