Privacy
Effective September 24, 2026. The short version: your audio never leaves your iPhone, we don't keep your transcripts or notes, and there is no advertising or tracking.
What stays on your iPhone
Lecture recordings, transcripts, notes, flashcards, quiz results and your courses are stored on your device. Transcripts and notes are included in your iPhone's own backup if you use one; recordings are excluded from it. Transcription happens on your iPhone using Apple's on-device speech recognition; audio is never uploaded.
What is sent to generate notes
When you tap Generate notes, the text of that lecture's transcript — with your bookmarks, the course name, and short summaries of up to three earlier lectures in the same course — is sent to our server (Google Cloud Functions) and from there to Anthropic, whose Claude model writes the notes. The result is sent back to your iPhone. We do not store the transcript or the notes on our server. Anthropic processes the text under its commercial terms, which do not allow it to train models on this data.
What our server keeps
- An anonymous account identifier, created automatically. We don't ask for your name, email or phone number.
- How many lectures you generated notes for this month, and how much processing that used, to enforce the free tier.
- If you subscribe: the subscription's product, expiry date and Apple transaction identifier, so Pro works. Payment is handled entirely by Apple; we never see card details.
We use Google Firebase (Authentication, Cloud Functions, Firestore) to run this, and Firebase App Check to confirm requests come from the real app.
What we don't do
No advertising, no third-party analytics, no tracking across apps or websites, and we never sell or share your data.
Deleting your data
Delete a lecture or course in the app and it is gone from your iPhone, including its audio. Deleting the app removes everything stored on the device. To have the server-side records above deleted, send a request through the support page.
Children
Chalkdust is not directed at children under 13.
Changes
If this policy changes, the new version will be posted here with a new effective date.