Privacy
The short version: the editor computes on your device, and nothing you type is sent anywhere by us.
Everything stays on your device
The editor computes where it runs. Expressions, sessions, their histories and the zoom are kept in the app's own storage on your device (the browser's local storage); deleting a session, or the app or the site data, removes them. There are no accounts, no cookies, no analytics and no telemetry — the source is public, and none of that is in it.
The apps and the stores
The Android and iOS apps carry everything they need and make no network requests: nothing you type ever leaves the phone. Installing them through Google Play or the App Store means Google or Apple collect their own data — downloads, crashes, device statistics — under Google's and Apple's privacy policies; of that, the developer only ever sees aggregate statistics.
This website
These pages are served by GitHub Pages, which logs visits (your IP address) as any web host does — see the GitHub Privacy Statement. The derivations on the front page carry their own rendering and load nothing else. The editor page fetches its Python runtime (Pyodide, SymPy) from public CDNs — jsDelivr and PyPI's file host — the way any download does, so those services see that request; what you then type in the editor still stays in your browser.
If you write to us
The project has no chat and collects no messages. If you open an issue or a discussion on the GitHub repository, that is public and processed by GitHub under its own terms, and we see what you chose to post — nothing more.