1. Who is responsible for your data
MatheZeit UG (haftungsbeschränkt)
represented by the managing director Mats Lorenzen
Kallehoe 27
24988 Oeversee, Germany
Email: info@mathezeit.de
Register court: Amtsgericht Flensburg (Flensburg Local Court), HRB 18391 FL
Data protection officer
IITR Datenschutz GmbH, Dr. Sebastian Kraska
Marienplatz 2, 80331 München, Germany
Email: email@iitr.de
Phone: +49 89 1891 7360
When MatheZeit is used at school, the school is the controller under data protection law (Art. 4(7) GDPR, General Data Protection Regulation) for the processing of pupils' data. The school decides on the purposes and means, directs the use in lessons and knows which code belongs to which child. In this respect, MatheZeit UG acts as a processor (Art. 28 GDPR) on the basis of a data processing agreement.
2. Explained simply for children
At MatheZeit you do not have to give your name. You log in only with your code. You get the code from your teacher.
We save which tasks you have done, what was right or wrong and whether you asked for help. This helps the tasks fit you better. It also helps your teacher to help you.
If your teacher wants to help you, your teacher can see during the lesson what you are doing on your MatheZeit page right now. Your screen then shows that your teacher is watching. What you are doing is not saved. We only note that and when your teacher watched.
Your teacher can see your learning progress. This is there to help you and to give you the right tasks. You do not get a mark for it.
Sometimes your teacher looks at which children in the class need more practice right now. Only your teacher sees this, not your classmates. You always see only your own progress. Children's names are not put in a ranking.
Your teacher can also look at how you solved a task: what you placed where, or which number you typed in. For this, the task is built up again. No photo is taken of your screen.
The learning helper Mazio is an AI. That is a computer program, not a person. In the Knobelbox and in the Basiscamp you can talk to him about a task. For this he only gets the maths task and your answer, never your name or who you are. In the MatheZeiten Mazio helps you too, but there nothing is sent to another computer. We keep the conversations from the Knobelbox and the Basiscamp for three months so that we can make Mazio better. Your code, your class and the time are not stored there.
Your data is not sold, not used for advertising and not used to train an AI.
If you have a question, ask your parents or your teacher.
3. Principles
We process personal data on the basis of the GDPR, national data protection law (in Germany the BDSG, Federal Data Protection Act) and the school law provisions of the country in which the school is operated. We are guided by the principles of Art. 5 GDPR: data minimisation, purpose limitation, storage limitation and transparency.
A detailed description of the technical and organisational measures under Art. 32 GDPR is provided to schools in our Data Protection and Security Information for Schools.
4. When a child practises with MatheZeit
4.1 Login
Children log in at mathezeit.de/anmelden with an eight-character access code issued by the teacher. No names, email addresses or other personal details of the children are collected. The code is a pseudonym.
The codes are generated at random and cannot be derived from other codes. The number of login attempts is limited. Whether an entered code exists is not disclosed. Transmission and storage are encrypted, and access rights are restricted to what is necessary.
The code is transmitted only at login. After that, the login is carried by a session cookie (section 4.5); the code does not appear in any address bar or in any further request.
If a teacher optionally assigns a real name to a code, that name is stored in encrypted form. The key is derived from the teacher's PIN and is not held by us; the real name is technically not accessible to us.
So that a child can recognise itself without a name, it receives a number within its class and, derived from that number, a pseudonym with an animal motif, for example “Loyal Crocodile”. Number and pseudonym apply only within the class and, without the teacher's list, do not allow any conclusion to be drawn about a specific person.
4.2 Which learning data is generated
Under the pseudonymous code we store:
- tasks completed and results (correct or incorrect)
- the answer given, in order to recognise recurring misconceptions
- tasks skipped and the number of attempts
- time and duration of work on a task
- number of hints used
- difficulty level and task type
- indicators of learning progress calculated from this, such as the success rate and how independently the child worked
This data is used for the evaluation of learning progress by the teacher and for controlling the selection of tasks. No processing for advertising or other purposes takes place.
Legal basis: Art. 6(1)(e) GDPR in conjunction with the school law and data protection provisions of the respective country (for schools in Germany, for example § 11 SchulDSVO SH, the School Data Protection Ordinance, in Schleswig-Holstein).
4.3 How tasks are adapted
The learning environment adapts the task type and difficulty to the child's learning progress. Only pseudonymous learning data is evaluated for this, such as the success rate at the first attempt and recurring error types. The adaptation serves individual support. No automated decision with legal or similarly significant effect within the meaning of Art. 22 GDPR takes place. The selection of the next task follows fixed rules set by us, based on the results of the most recently solved tasks, and affects only this selection. The teacher can instead choose a fixed difficulty level for a child.
4.4 What the teacher sees
The teacher sees the learning progress of the children in their own classes: which tasks were worked on, how many of them were correct, which answers the child gave, how often hints were used and the indicators calculated from this. Access is limited to the teacher's own classes.
Login times, usage times and working durations of individual children are not shown to the teacher. We use the time and duration of work on a task only by machine, for task control (section 4.3) and for assignment to the lesson.
View of the child's work. For a completed task, the teacher can display how the child solved it; for this, the task is rebuilt in the teacher's browser from the stored answers (section 4.2). No screen image is transmitted and nothing is recorded. The purpose is to recognise misconceptions; the view is visible only to the teacher of the child's own class and is deleted together with the learning data (section 9).
Klassenbild. In addition, the teacher can set up the “Klassenbild” (class overview) for a class (this is the name used in the application; hereinafter also “classification”). The teacher places the learning progress within the class in order to identify support needs and to provide tasks in a targeted way. This classification is profiling within the meaning of Art. 4(4) GDPR. This processing is carried out exclusively on a pseudonymous basis, serves educational support and not the evaluation of the child's personality, and is safeguarded by the following measures:
- The function is deactivated by default. It is deliberately activated by the teacher for each class and can be switched off again at any time.
- It is unlocked only after the teacher has completed a mandatory didactic introduction and confirmed that the evaluation serves targeted support and not grading or performance assessment.
- The teacher can exclude individual children from the evaluation; no classification takes place for them.
- Only subject-related competence indicators are evaluated (such as the success rate and error types per competence area). Login times and usage durations are not included in the classification.
- Support needs are measured against a fixed subject-related threshold, not against a ranking. The display shows the median and range of the class; no ranking of the children is formed or displayed.
- The classification takes place only once there is a sufficient data basis. If too little data is available, it does not take place, so that individual children are not singled out.
- The evaluation is visible only to the teacher of the class. Pupils see only their own learning progress, not that of other children.
- No automatic consequences for the child follow from the evaluation. Every educational decision is taken by the teacher; no decision based solely on automated processing within the meaning of Art. 22 GDPR takes place.
- We describe the underlying classification logic (competence areas, threshold, minimum data basis) to schools in the Data Protection and Security Information for Schools (section 3), Art. 13 and 14 GDPR, recital 60.
- No special categories of personal data within the meaning of Art. 9 GDPR are processed. The underlying learning data is deleted in accordance with section 9.
- A data protection impact assessment under Art. 35 GDPR is maintained for this processing.
- No personality profile going beyond the purpose of educational support is created.
Live view during the lesson. During a lesson that has been started, the teacher can see what an individual child in their class is currently doing on the learning page, in order to help that child specifically. For this, the structure of the learning page is transmitted to the teacher's browser and reproduced there.
The following limits apply to this function:
- Visible to the child. As long as the transmission is running, it is shown to the child on the child's screen.
- Only on explicit viewing. Nothing is captured on the child's device until a teacher opens the view. Capture ends when the view is closed.
- Only one child from the teacher's own class. The view can be opened only for children who belong to one of the logged-in teacher's own classes. The server checks this on every access.
- Only during a lesson that has been started. Without a running lesson, the view is blocked on the server side. A lesson ends automatically 90 minutes after it starts, or earlier if the teacher ends it.
- No recording. The transmission is passed on in working memory and is not stored in a database. We only log which teacher watched which access code and when, so that unauthorised watching can be checked. This log contains no content, is only viewed by the school management where there is a specific reason, and is deleted after 90 days.
- Only the learning page. What is transmitted is the content of the MatheZeit page, not the rest of the screen and nothing from other applications. Entries in task fields are part of the work on the task and are also visible; there are no other input fields in the learning area.
- No mouse movements. Movements of the pointer are not captured.
- No evaluation. No indicators are formed from the live view. It is not included in the Klassenbild.
Activity display. Independently of this, during the lesson the teacher sees in an overview which children are currently practising and which task or MatheZeit they are working on. This status is held only in working memory and ends with the lesson.
Instructions to the class. During a lesson that has been started, the teacher can direct the children of their class jointly to a specific task or end their login. This is a teaching instruction to the whole class; it is not directed at individual children, and no data about individual children is generated.
Legal basis: Art. 6(1)(e) GDPR in conjunction with the school law of the country in which the school is operated (in Germany, for example § 11 SchulDSVO SH: conduct and supervision of lessons).
4.5 Session and cookie
After login we set a technically necessary cookie:
| Name | Purpose | Duration |
|---|---|---|
mz_schueler_sitzung | Recognise the logged-in child so that the code does not have to be entered again | 45 minutes without activity, at most 12 hours, and in any case until the end of the day. In addition, the browser deletes it on closing |
The cookie cannot be read by JavaScript and contains no information about the child, only a random session key. We set no further cookies in the pupil area. No consent is required for this technically necessary cookie (Art. 5(3) of the ePrivacy Directive as implemented in national law; in Germany § 25(2) no. 2 TDDDG, Telecommunications Digital Services Data Protection Act).
For the session we store on the server the session key in hashed form, the access code, the class, the expiry time and the time of the last activity, as well as a key value of the IP address that changes daily and cannot be traced back to the address. Because tablets in class sets are passed between children, a session ends
- after 45 minutes without activity,
- after 12 hours at the latest,
- in any case at the end of the day.
On a shared device, the login page shows who is still logged in there, so that no one inadvertently continues working under someone else's login.
4.6 Evaluations beyond the class and reports
Hints on misconceptions. Once a week we check for each class whether the wrong answers show a widespread misconception. Only aggregated information for the class as a whole is analysed, never data of individual children. The teacher only receives a hint for the class as a whole, and only if it is based on at least three children and the class has at least ten children. Which children are affected is neither analysed nor shown nor stored.
Comparison values. So that the teacher can put the level of the class into context, we form comparison values from the aggregated class values of the participating schools, and only from at least five classes from at least three schools. Values of individual children, classes or schools cannot be identified from them.
Improving the tasks. From the completed tasks we form counts per task, for example how often it was solved and which wrong answers are common, and use them to improve the tasks. Counts are only formed from at least ten attempts from at least three classes and contain neither code nor class nor school.
The school as controller can object to both at any time; the school's classes are then no longer included.
Reporting a task. If a child or a teacher finds an error in a task, they can report it. We transmit the task, the state of the task and an image of the task area only, for children also the year group, but neither code nor class. Children cannot enter any text; teachers can add a note. Reports are deleted once they have been dealt with, at the latest after twelve months.
5. The learning assistant Mazio
Mazio gives children feedback and hints while they practise. A language model is used at only one point: in the conversation about a task in the Knobelbox and in the Basiscamp. No language model is used in the MatheZeiten; Mazio's feedback there is generated within the learning environment itself, without tasks or answers being transmitted to a provider. The following sections 5.1 to 5.3 concern only the conversation in the Knobelbox and in the Basiscamp.
5.1 What is transmitted
Only the task and the answer given are transmitted to the provider of the language model: without name, without login code, without IP address and without session data. The provider therefore receives no information that would allow attribution to a specific child.
There is no free text input in the learning path through which a child could enter personal details.
The request never reaches the language model directly. It passes through our own servers; only there is the request to the model assembled and forwarded. The provider sees only a request from our server.
5.2 Where processing takes place
The learning environment, the task control and the storage of learning data are operated in Germany. For linguistic feedback we use only models that are operated in data centres within the EU:
| Model | Operation |
|---|---|
| Claude (Anthropic) | via our infrastructure provider Amazon Web Services, accessed via Frankfurt am Main, processing exclusively in EU data centres (Frankfurt, Stockholm, Milan, Aragón, Ireland, Paris) |
| Mistral AI | via our infrastructure provider Amazon Web Services, within the EU (accessed via Frankfurt am Main) |
| Self-hosted language model | on our own processing server in Frankfurt am Main, without an external provider |
The providers involved are listed in section 8.
5.3 Storage of content
At the provider of the language model, the transmitted content is not stored (the account is set to “no data retention”), not used to train AI models and not passed on to third parties. The models are operated at our infrastructure provider in environments to which the model providers have no access.
On our side, we record the task, the answer given and the course of the conversation, without access code, without class, without time of day (only the date) and without any other identifier of the child. We do not link these records to the learning data. We use them solely to check and improve the quality of the hints; deletion after 90 days (section 9).
5.4 Not an assessment tool
Mazio supports practising. It does not carry out any performance assessment and is not intended for that purpose. All educational and performance-related decisions are taken by the teacher.
5.5 Labelling as an AI system
Mazio is an AI system within the meaning of Art. 3(1) of Regulation (EU) 2024/1689 (AI Act). MatheZeit UG is its provider (Art. 3(3)); schools that use MatheZeit in lessons are deployers (Art. 3(4)). Children are informed in the application that the hints come from a computer program and not from a person (Art. 50 AI Act); this section supplements that notice but does not replace it.
Mazio gives hints and asks questions about the task a child is currently working on. It does not award marks and takes no decisions on admission, promotion to the next year, support needs or educational level; such decisions are taken by the teacher. Mazio is not a high-risk AI system within the meaning of Annex III of the AI Act. We provide schools with our classification and the reasons for it, and we will review it as soon as the European Commission has finally adopted its guidelines on classification.
5.6 What the teacher sees of this
During a lesson that has been started, the teacher can read along in the live view (section 4.4) which hints Mazio is currently giving a child. Afterwards, the conversations are not attributed to any child. We explain to teachers in the application how Mazio works, with rules and examples. Mazio's hints are not included in any assessment.
6. When you use MatheZeit as a teacher
6.1 Account
On registration we store your name, email address and school affiliation. Passwords are stored exclusively as a cryptographic hash, never in plain text. Login takes place at mathezeit.de/anmelden via a system operated by us on our server in Germany.
For the first login and if you forget your password, we send a six-digit code to your email address. It is valid for 20 minutes and is used to set a new password. The same login procedure applies in the MatheZeit app.
Legal basis: Art. 6(1)(b) GDPR (performance of a contract).
6.2 Cookie
| Name | Purpose | Duration |
|---|---|---|
mz_teacher_session | Recognise the logged-in teacher | 24 hours; 7 days when logging in via an invitation link |
We set no further cookies. There are no analytics cookies, no tracking and no comparable services. No consent is required for the technically necessary session cookie (Art. 5(3) of the ePrivacy Directive as implemented in national law; in Germany § 25(2) no. 2 TDDDG).
6.3 Support and feedback chat
Via the chat in the application, teachers can send us questions, feedback and error reports. In doing so, the name, work email address and message text are processed and stored by us so that we can follow the history of the conversation.
The messages are processed exclusively on our own servers in Germany and are not passed on to third parties.
Legal basis: Art. 6(1)(b) GDPR.
6.4 Newsletter
If you consent to the newsletter, we use your email address to send you information about MatheZeit. You can withdraw your consent at any time via the unsubscribe link in every message or by email to info@mathezeit.de.
Legal basis: Art. 6(1)(a) GDPR.
6.5 Events and professional development
We offer online events and professional development for teachers (mathezeit.de/veranstaltungen).
Registration. When you register, we process your first name, last name, email address, the chosen date and, if you provide it, your school. The school appears only on your certificate of attendance. If you reach us via a link that names its source, for example from a professional development portal or a letter, we store that source with the registration to see which routes lead teachers to us. To prevent misuse, we store the IP address only in hashed form.
Emails about the event. After registering you receive a confirmation with a calendar entry, reminders before the date (one week before, the day before and shortly before the start with access to the room) and afterwards the certificate or a note about the recording. These emails are part of running the event and contain no advertising. You can cancel at any time via the link in every email.
Attendance and certificate. When you enter the room via your personal page, we store the time. This tells us that you attended, and only then do we issue a certificate. It carries a verification number. Anyone who knows the number, such as your head teacher, can check its authenticity on our website; it shows your name and the title, date and duration of the event.
Running the event. Events take place in video conferencing software that we operate ourselves on our server in Germany. Your IP address, displayed name, chat messages and technical connection data are processed for the duration of the event only. You switch your camera and microphone on and off yourself. If an event is recorded, we say so beforehand; only what the presenters show and say is recorded.
Feedback. After the event we ask for brief feedback. It is voluntary and evaluated without names.
Notices of new dates. We only send notices of further dates if you expressly ask for them and have confirmed your email address via a confirmation link. You can withdraw your consent at any time.
Registration via a professional development portal. If you register via a state portal, such as the Niedersächsisches LernCenter (NLC), FIBS in Bavaria or the Fortbildungssuchmaschine NRW, the portal operator passes on the details needed to run the event. Processing within the portal is governed by the operator's privacy policy. We use data from such registrations exclusively to organise the event concerned.
Legal basis: Art. 6(1)(b) GDPR for registration, event emails, running the event and the certificate; Art. 6(1)(f) GDPR for preventing misuse and evaluating the source (legitimate interest: secure operation and knowing which routes lead to our professional development); Art. 6(1)(a) GDPR for notices of new dates.
7. When you visit our website
7.1 Server log files
When a page is accessed, the web server automatically stores:
- IP address in shortened form (the last address block is removed before storage, e.g.
192.0.2.*) - date and time
- page accessed
- HTTP status code
- browser and operating system
This data is used for operation and troubleshooting. It is not combined with other data sources. The log files are deleted automatically after 14 days.
A separate error log contains the full IP address for the purpose of defending against automated attacks. It is evaluated solely for this purpose and is likewise deleted after 14 days.
Legal basis: Art. 6(1)(f) GDPR (security and stability of the service).
7.2 Fonts
We deliver fonts from our own server. Our server obtains them from the font service Bunny Fonts without passing on any visitor data. Your device connects neither to Bunny Fonts nor to Google.
7.3 No embedded third-party content
We deliver the images, design elements and scripts of our pages from our own server. External content delivery networks are not embedded.
7.4 Contact form
If you use the contact form, we process the details you enter (name, email address, organisation, subject and message) and the time of submission. To prevent misuse, we additionally store the IP address in hashed form and the browser identifier. The data is deleted as soon as your request has been dealt with.
Legal basis: Art. 6(1)(b) GDPR; for the prevention of misuse, Art. 6(1)(f) GDPR.
7.5 No advertising or analytics services
We use no social media plugins, no external analytics services and no advertising tracking.
8. Who processes data besides us
Processing chain when used at school: School (controller) → MatheZeit UG (processor) → the providers listed below.
| Provider | Purpose | Location |
|---|---|---|
| Hetzner Online GmbH | Hosting of the platform and the learning data, and of the video conferences for events | Germany (Nuremberg) |
| OVH GmbH (OVHcloud) | Processing server for the learning assistant | EU (Frankfurt am Main) |
| Amazon Web Services EMEA SARL | Operation of the language models; receives tasks and answers without identifier (section 5.1) | EU data centres (section 5.2); parent company in the USA, see below |
| IONOS SE | Sending emails to teachers (sign-in, confirmations, events) | Germany |
All processors process the data exclusively within the European Union. No personal data is transferred to third countries. Amazon Web Services only receives tasks and answers without an identifier. Because the company belongs to a group headquartered in the USA, access by authorities under US law cannot be completely ruled out; even then, only this content without an identifier would be affected. Such disclosure requests are not a ground for transfer (Art. 48 GDPR). Data processing agreements are in place with all processors; we provide the evidence to schools as controllers on request.
Beyond the providers in this table, we do not pass on any data to third parties.
9. How long we store data
| Data | Retention period |
|---|---|
| Server log files | 14 days |
| Children's learning data | until deleted by the teacher or the school, at the latest 18 months after the code was last used |
| Pupil codes and classes | until deleted by the teacher, at the latest 18 months after the last use |
| Activity status for the view during the lesson | no storage; working memory only, ends with the lesson |
| Log of the live view (who watched when) | 90 days |
| Records of the learning assistant (without identifier) | 90 days |
| Reports of faulty tasks | until dealt with, at most 12 months |
| Teacher account | until deleted by the teacher or on request, at the latest 18 months after the last login (with a reminder four weeks beforehand) |
| Children's session (cookie and server entry) | 45 minutes without activity, at most 12 hours, at the latest at the end of the day |
| Session cookie (teachers) | 24 hours; 7 days with invitation link |
| Login code by email (teachers) | 20 minutes |
| Contact form | until the request has been dealt with |
| Support and feedback chat | 24 months |
| Newsletter consent | until withdrawn |
| Event registrations without attendance | 3 months after the date |
| Attendance and certificate (name, school, date, verification number) | 3 years after the date; email address and source 3 months after the date |
| Consent to notices of new dates | until withdrawn; unconfirmed requests 30 days |
10. Your rights
You have the right of access (Art. 15), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18) and data portability (Art. 20).
Objection. Insofar as data is processed on the basis of Art. 6(1)(e) or (f) GDPR, you may object at any time on grounds relating to your particular situation (Art. 21 GDPR). For pupils' data, please address the objection to the school; the school examines it and we implement it, for example by setting the task adaptation for the child to a fixed level chosen by the teacher.
To do so, please contact info@mathezeit.de.
When MatheZeit is used at school, please address requests concerning pupils' data to the school as controller. We support the school in fulfilling these rights. The records of the learning assistant contain no identifier of the child and are not linked to learning data (section 5.3); they therefore cannot be attributed to any person.
11. Right to lodge a complaint
You may lodge a complaint with a data protection supervisory authority. As a rule, the competent authority is that of the country or federal state in which the school or the data subject is located. For Germany, an overview of the authorities of the federal states is available at bfdi.bund.de.
There is no single authority for all countries. The European Data Protection Board lists the supervisory authorities of all member states of the European Union and the European Economic Area at
edpb.europa.eu
12. Contact for data protection matters
MatheZeit UG (haftungsbeschränkt)
Kallehoe 27, 24988 Oeversee, Germany
Email: info@mathezeit.de
Last updated: 13 October 2026
This version is a translation of the German version dated 28 September 2026 and is provided for information purposes. In the event of discrepancies, the German version prevails.