Effective date: 19 September 2026 · Applies to the Android app "Tella" (com.sparkfall.tella) and the website tella.sparkfall.app, published by Sparkfall.
In short: Tella has no accounts, no ads, no analytics or tracking SDKs, and collects no personal information. Your location is used only to generate spoken narration about your surroundings, and it is never linked to your identity.
Location. While you use Tella (including with the screen off while the guide is running), the app reads your device's location to find out where you are and what is nearby. To do that, your coordinates are sent to:
Location is used transiently to answer each request. We do not build a history of where you have been, and no location data is linked to your identity. Tella does not request background location — location is only read while the app (or its visible guide notification) is running.
Anonymous device token. On first launch the app registers with our gateway and receives a random identifier. It contains no personal information and cannot be tied to you; it exists solely to enforce a fair daily usage limit. Usage counters are deleted automatically within about two days. Before they are deleted we add them into a daily total for all users combined — how many people used Tella, and how much of the daily allowance they used — so we can size that allowance sensibly. Those totals are just numbers: they contain no device token and nothing that could point back to you or your phone.
First-use steps. The first time the app reaches each of a few setup steps — opened, location permission asked, allowed or declined, first position found, first story asked for and started, second and third story told, the demo walk started — it tells our gateway once, so we can see where new users get stuck. Each message contains only the name of the step and the app's version number: no device token, no location and no identifier of any kind, so messages cannot be linked to each other or to you. They are added into daily totals and deleted within about two days, like the usage counters.
Tour summaries. While a tour runs (and when you ask about places on the map, or play the demo walk — reported the same way, marked as a demo, with the demo's own scripted position and never yours), the app sends our gateway a running summary of it, so we can see which stories people listen to and which they cut short: a random number made up for that one tour, when it started and how long it ran, the app version and language, whether you pressed Stop, whether location was available on your phone at that moment (on, switched off, or not permitted) and how long it took to get a position if it did, and for each story the name and database id of the place it was about, whether you were standing, walking or riding, and how the story ended (played to the end, skipped, paused, stopped). When the guide goes quiet while a tour is running it also records which of its own rules is holding the next story back - waiting out the gap after the last one, waiting for you to move on, paused, exploring the map, or waiting for a call or navigation prompt to end - so that an unexplained silence can be diagnosed; that is about the app, not about you, and carries no position. The summary is sent with the anonymous device token so that only the app can send one, but the token is not stored with it: nothing links one tour to another or to your phone. Summaries are deleted after 14 days; only daily totals are kept after that.
App integrity check. During registration the app may ask Google Play to attest that it is a genuine, unmodified copy of Tella (Google Play Integrity API). This check is handled by Google Play services under Google's privacy policy.
Speech. Narration is spoken using your device's built-in text-to-speech engine. The audio is generated on your phone and never uploaded.
tella.sparkfall.app shows Tella's explore mode in a browser: you pan a map, pick a place and hear its story. It uses no account, no cookies and no analytics. The point of the map you look at, and the place you pick, are sent to our gateway server to find nearby places and fetch or write that place's story; the search box sends your search text to Photon; map tiles are loaded from OpenStreetMap by your browser (which, like any website, lets OpenStreetMap see your IP address), and satellite imagery, if you switch it on, from Esri's ArcGIS Online in the same way; the city guide pages (tella.sparkfall.app/en/audio-guide/ and its twins in other languages) load a few Esri satellite tiles for their map preview and place photographs from Wikimedia Commons in the same way and send nothing else; place photographs come from Wikimedia Commons; opening the "About" panel loads the promo video's preview image from YouTube's image host, and the video itself is embedded from YouTube's no-cookie domain only if you press play. The story is read aloud by your browser's own speech engine and never uploaded. To keep a fair daily usage limit without an account, the gateway derives a temporary identifier from a one-way hash of your IP address and the date; the address itself is not stored, and the identifier cannot be linked from one day to the next. Its usage counters are deleted within about two days, like the app's.
All network traffic uses HTTPS. Our servers keep no personally identifiable information; the only stored data about your device is short-lived usage counters keyed to the anonymous device token, plus the combined daily totals described above, which identify nobody. Settings stored on your phone (chosen language, narrator style, and the device token) are removed when you uninstall the app, and are excluded from Android cloud backups.
The services above process data under their own policies: OpenStreetMap Foundation, Wikimedia Foundation, komoot (Photon), Cloudflare, DeepSeek, Google Play services.
Tella is a general-audience app and is not directed at children under 13. It collects no personal information from anyone, including children.
You can revoke the location permission at any time in Android settings (the guide simply stops narrating). Uninstalling the app removes all locally stored data.
If our data practices change, we will update this page and its effective date before the change takes effect.
Questions or requests: support@sparkfall.app