Carstack Privacy Policy

1. Introduction

We respect your privacy and are committed to protecting it. This Privacy Policy explains our practices regarding your data when using Carstack, a driving logger app for iOS.

Carstack is built to be as private as a location-based app can be: there are no traditional accounts, no analytics, and no advertising. Your drives are identified by an anonymous device identifier. The only personal information the app ever holds is what you choose to add yourself — an optional public username and avatar for the social feed.

2. Information We Collect

2.1 Location and Route Data

Recording drives is the core purpose of Carstack. While a drive is being recorded, the app collects your precise location — including in the background, so recording continues while your phone is locked or you're using other apps. This produces the route line of your drive along with its start, end, and top-speed locations. Location is only recorded during an active driving session, never continuously.

Outside of recording, your approximate location is used transiently for convenience features: the map tab looks up which city you are in (to compute your coverage statistic), and the fuel log suggests nearby stations and chargers. These lookups are not stored as part of any drive.

2.2 Drive Statistics

For each drive, the app stores when it started and ended, its duration and moving time, distance, average and top speed, which of your cars you attributed it to, and whether it was started manually or automatically.

2.3 Weather Conditions

Weather conditions along your drive are captured using Apple's WeatherKit and stored with the drive. Weather requests are made through Apple's frameworks and are subject to Apple's privacy policy.

2.4 Fuel and Charging Logs

If you log a fuel stop or an EV charge, the app stores the time and location of the stop, the station or charging spot name, the amount of fuel or energy, and the price you entered. When you log a charge at a private spot (such as home charging using the "Other" option), no location is saved with that entry at all.

2.5 Anonymous Device Identifier

The app generates a random identifier that is stored securely on your device. It is used solely to keep your synced drives together and contains no personal information — we cannot link it to your name, email address, or Apple ID.

2.6 Diagnostic Crash Reports

If the app crashes, a technical report (the error message and stack trace, linked to your anonymous device identifier) is sent to our server so the bug can be found and fixed. Crash reports contain no location, route, or profile data.

2.7 Social Profile (Optional)

If you choose to join the social feed, you can pick a public username, upload an avatar photo, and list the cars you drive. All three are optional, provided by you, and linked to your anonymous device identifier. Usernames are unique across the app. You never have to create a profile to use Carstack.

3. Information We Don't Collect

Carstack has no account system and does not collect, store, or transmit any of the following:

• Personal information such as your name, email address, or phone number — the only identity we ever hold is the username and avatar you optionally choose for the feed
• Contacts, photos (other than an avatar you explicitly pick), or other device content
• Usage analytics or behavioral tracking
• Advertising identifiers

We do not sell your data or share it with advertisers.

4. How Your Data Is Stored

Your drives are stored locally on your device first, so the app works fully offline. Recorded drives and fuel logs are then synced to our server so your data is backed up.

Your GPS data is encrypted and stored securely for each device. Synced data is keyed to your anonymous device identifier: your routes, coordinates, and full drive data are never visible to any other device. The only thing other users can ever see is the summary activity described in the next section.

Our server is hosted on Railway, a cloud hosting provider. Avatar images are stored on Tigris, an object storage provider. Data is encrypted in transit (HTTPS) and at rest.

5. The Social Feed

The feed shows recent driving activity from Carstack users. For each completed drive it can show a duration, a distance, the car it was driven in, and a rough recency ("2h ago"); for a fuel stop or charge, the amount of fuel or energy and the station name; and while a drive is being recorded, that a user is currently on the road along with the running time and distance.

If you have created a profile, this activity appears under your username and avatar. If you haven't, it appears anonymously as "Someone" with no identity attached.

The feed never shows routes, maps, coordinates, addresses, station locations, or fuel prices. When you filter the feed to "Nearby", your approximate location is used only to select which activity to show you — it is compared on the server and never shown to anyone.

Avatar images are served from a public URL under a random, meaningless file name that cannot be traced back to your device identifier.

6. Share Cards and Privacy Zone

You can export a share card image of a drive. Share cards are generated on your device and are only shared when you choose to share them. With your permission, they can be saved to your photo library.

The Privacy Zone setting trims the beginning and end of your route on share cards, so the exact locations where your drives start and end (such as your home) are not revealed when you share. Full routes always stay in the app.

7. Third-Party Services

Carstack does not integrate with any analytics providers or advertising networks. The only third parties involved are:

• Apple — Apple Maps, WeatherKit, CarPlay, and Live Activities are provided by Apple's on-device frameworks and are governed by Apple's privacy policy.
• Railway — hosts the server that stores your synced drives, as described above.
• Tigris — stores avatar images you upload for your feed profile.
• OpenStreetMap — city boundaries for the map's coverage statistic are looked up by our server against OpenStreetMap's public services. These requests come from our server, include no device identifier, and results are cached so lookups are rare.
• Exchange rate service — converting fuel prices between currencies uses daily reference rates fetched from a currency rate API. These requests contain only currency codes and dates, never personal data or amounts.

8. Data Retention and Deletion

You can delete individual drives and fuel logs in the app at any time. Deleting a drive also removes it from the feed. Deleting the app removes all locally stored data from your device.

You can request removal of all of your data from our server — including your username, avatar, cars, and all synced drives — at any time by emailing support@wojtek.im and including your device identifier (UUID), which you can find in the app's settings. Because your data is linked only to this anonymous identifier, we need it to locate and delete your data.

9. Data Security

Data on your device is protected by iOS security features, and the anonymous device identifier is stored in the system keychain. Data in transit to our server is encrypted using HTTPS. No method of transmission or storage is 100% secure, but the minimal amount of personal information in our database significantly limits what could be exposed.

10. Children's Privacy

Carstack is a driving app and is not directed at children. We do not knowingly collect any data from children.

11. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last Updated" date.

12. Contact Us

If you have any questions about this Privacy Policy, please contact us at support@wojtek.im.