Privacy & licensing

Privacy

This application has no accounts of its own. Your saved progress is stored on this device, in your browser's own storage (a browser feature called IndexedDB), and stays there unless you turn on syncing in Settings. Syncing is opt-in and off by default: turning it on creates an account only on the separate sync server described below, and lets your finished sessions and preferences follow you to another device. If you never turn it on, nothing changes: your saved progress stays only on this device.

To restore breadcrumb navigation within this browser tab, the app keeps only a bounded list of session stage IDs and a bounded per-session count of released Opdrachten in browser history and tab-local session storage. It never stores a brief, chat assistant response, or other learner content there.

While you review a session, a pasted chat assistant response is held only in the page's transient form state; it is not saved to your device.

Downloaded backups are files you manage; this application does not save them to your device on its own.

Application code transmits your saved progress only if you turn on syncing, and even then only your finished sessions and preferences; pasted chat assistant responses, in-progress sessions, and imports are never transmitted. There are no analytics, telemetry, advertising, or tracking.

Vercel receives ordinary requests for the public application, content, media, and attribution files. External chat is separate from this application and follows the privacy terms of the chat service you choose.

This application does not guarantee offline use: public app files, content, media, and attribution can be requested when needed. You are responsible for keeping any backup you want to retain.

See Licensing for the third-party image-credit boundary.

Sync across devices

When you turn on syncing, your finished sessions and preferences are sent to a self-hosted sync server the developer operates, on a host located in Germany. Sessions you have not finished yet, and anything you paste into an exercise, are never sent there.

This storage is not end-to-end encrypted, so the operator can read what is stored there; that is ordinary server-side access, not a promise of stronger confidentiality.

A device that has synced keeps a sync credential in localStorage, a separate browser storage feature from the one your saved progress uses, so it can reconnect without asking you to sign in again each time. Turning sync off on a device, or erasing its saved data, removes this credential from that device.

Turning sync off is different from deleting your data from the sync server. Turning it off stops sending new data but leaves what is already stored on the server; deleting your server data, from the same Settings screen, permanently removes it from the server. Neither action changes your saved progress already stored locally on this or any other device.

Licensing

Application code is licensed under MIT.

Project-authored prompts, lessons, curricula, exercises, and content documentation are licensed under CC BY-SA 4.0.

Third-party media keeps the licence recorded for that individual media item; it does not inherit the project content licence. Its complete credit appears directly below each opened practice image.

Third-party browser software notices cover the reviewed packages present in this static release. Read third-party software notices.

These project licence claims do not license learning-material, confidential DUO material, or other third-party material.