1. Controller

The controller for this website is Guido Witt-Dörring, Mühlgasse 3, 2322 Zwölfaxing, Austria. For privacy-related questions or to exercise your rights, you can contact us at guwidoe [at] gmail.com.

2. Hosting and technical server data

This website is provided through Vercel. When the website is accessed, technically required connection data such as IP address, access time, requested URL, referrer information, browser/device data and similar log data may be processed to deliver the website, ensure security and detect misuse.

Where personal data is processed in this context, the legal basis is our legitimate interest in the secure and stable operation of the website (Art. 6(1)(f) GDPR).

3. Scenario data and feedback form

The GroupMixer tool does not transmit entered participant names or result data to our servers or to backend services under our control. Product telemetry sends coarse usage events; when solver failures occur it may also send an anonymized scenario structure in which people, groups, attribute names and attribute values are replaced with technical placeholders. The full feedback form can also transmit the message you enter, optional contact details and optional browser diagnostics. Non-anonymized scenario contents are never sent anywhere.

4. Web analytics

This website uses Vercel Web Analytics and Convex telemetry in a deliberately data-minimised configuration. It does not set analytics cookies, user accounts or browser fingerprints. In addition to page views, individual product events may be processed with a server-side timestamp, a random sessionStorage-based session identifier that expires after inactivity or a browser session, and coarse categories such as participant/group/session-count buckets, whether rules/preferences are present, locale, embedded parent origin, and coarse technical failure diagnostics.

Product telemetry does not transmit participant names, group assignments or free text, and it is not queued for offline delivery. When solver failures occur, GroupMixer may automatically transmit an anonymized scenario structure without original names, group labels, attribute names or attribute values so that unsolved configurations can be reproduced and improved. Where personal data is processed for reach measurement or failure analysis, the legal basis is our legitimate interest in a privacy-friendly analysis and improvement of the website (Art. 6(1)(f) GDPR).

5. Browser-local storage and offline functions

GroupMixer stores drafts, scenarios, results, UI state and similar functional data locally in the browser (for example via IndexedDB, localStorage, sessionStorage and the service worker cache) so that the app works as intended. This data generally remains on the user’s device and is not used for server-side collection of tool content.

This browser-local storage supports scenario editing, draft recovery and offline use. Quick Setup and the scenario editor use the same saved scenario, and advanced settings not shown in Quick Setup remain intact. Isolated guide examples become saved scenarios only after an explicit handoff.

6. Recipients and storage periods

The main external technical recipients are Vercel for hosting and delivery plus the named analytics/telemetry services. Feedback messages may also be processed by configured services for delivery, notification or internal issue tracking. Where we can influence storage periods, data is only processed for as long as necessary for secure operation, error analysis, feedback handling and privacy-friendly reach measurement. Otherwise, the provider’s retention and deletion rules apply.

7. Data protection rights

Where personal data is processed in individual cases in connection with hosting, log data or reach measurement, the statutory data protection rights apply, in particular rights of access, rectification, erasure, restriction of processing, data portability and objection. You also have the right to lodge a complaint with the Austrian Data Protection Authority.