Euler is an iPhone app by Dylan Cantor ("I", "me") that generates music from your walk. This policy explains what the app does with your data.
The short version
- Euler uses your location only while the app is open, to steer the music.
- Your location goes to Euler's music server in real time and is not stored, sold, shared or used for advertising or tracking.
- Walks you make are stored only on your iPhone. They leave it only if you tap Share, which creates a link that you send yourself.
- There are no accounts, ads, analytics or third-party tracking SDKs.
What the app uses and why
Location (while using the app). When you start a walk, the app sends your position (latitude, longitude, accuracy) and compass heading several times per second to Euler's music server. The server uses them only to choose which musical styles to blend and sends audio back. Nothing is written to disk and nothing is linked to you. When the session ends, it's gone. If you don't grant location access you can still play the recorded walk.
Network connection. Live music is generated on a cloud server (GPU hosting by Modal Labs) and streamed to your phone over an encrypted connection. Like any internet service, the hosting provider may briefly process technical data such as your IP address to deliver the connection. Euler does not use it to identify you.
On your device only. The app remembers that you've finished onboarding, and keeps the walks you make or save. These stay on your phone and are deleted when you delete them or the app.
Walks you share. Tapping Share builds a link on your phone and opens the iOS share sheet; Euler itself uploads nothing. The link contains the walk's name, its musical styles, and the shape of the route (distances between stops in meters). It does not contain where the walk is, unless you turned on "Pin to this place" when making it; in that case the link includes the walk's real starting location and the app asks you to confirm before sharing. The walk is stored after the "#" in the link (https://dylancantor.com/euler/w#…), a part of web addresses that browsers do not send to the website, so dylancantor.com never receives it. Anyone you send the link to can see and walk it.
Walking a walk. When you play any walk, its layout (stops, styles, and, for pinned walks, location) is sent to Euler's music server together with your position, for the same real-time purpose described above, and is not stored.
Euler does not access your microphone, contacts, photos, health data or any identifier for advertising.
Children
Euler is suitable for all ages and does not knowingly collect personal information from anyone, including children under 13.
Changes
If this policy changes, the new version will be posted here with a new date. If a future version of Euler starts storing any data, the policy will say so before that version is released.
Contact
Questions: [email protected]