Privacy Policy
Effective October 16, 2026
Marker Hunter ("the app," "we") is an independent app made by Zachary Gruetzner in Texas. This policy explains what information the app uses, where it is kept, and the choices you have.
Information the app uses
Your location
With your permission, the app uses your phone's location while the app is open to find the historical markers near you and to confirm you are at a marker before stamping your passport. When you stamp a marker, the app saves the spot where your phone was and how accurate the reading was, along with the stamp. This stays on your phone.
You can change or turn off location access at any time in your phone's Settings app. Without location, the app still works but can't find markers near you or stamp visits.
Passports, stamps, and badges
Passport names (we suggest a first name or nickname), stamps, badges, trophies, spring break dates, and which markers you have heard or muted are saved on your phone only.
Settings
Your choice of narrator voice and other settings are saved on your phone only.
What we do not collect
- No accounts, names, email addresses, or phone numbers.
- No advertising, ad tracking, or selling of information.
- No analytics or usage tracking.
- No contacts, photos, or microphone access.
Features that use other services
- Maps: the map is provided by Apple Maps on iPhone (Google Maps on Android). Showing the map, and the blue dot for your position, is handled by that service under its own privacy policy.
- Directions: tapping Directions opens your phone's maps app with the marker's location.
- Reading aloud: inscriptions are read by your phone's built-in voices. The text is not sent to us.
- Reporting a marker or museum problem: tapping "Report a problem" opens your own mail app with an email to the Texas Historical Commission, filled in with the marker's or museum's details and, if you are within about a mile of it, your current location. You can edit or delete anything, and nothing is sent unless you tap Send. The email goes from your account directly to the Commission, not through us.
- Sharing: nothing is shared unless you tap Share. Shared messages include only the passport's first name and the badge or trophy, never a marker, place, or time.
Children
Marker Hunter is made for families. Children use the app through passports on a parent's or other adult's phone. Because this version collects no personal information and sends nothing off the phone, we do not collect personal information from children. We suggest using a first name or nickname for each passport.
Keeping and deleting your information
Everything the app saves lives on your phone. Deleting the app deletes all of it. We have no copy, so we cannot restore it.
Changes to this policy
Future versions may add optional features such as accounts, backup of your stamps, or email updates. Before any of those collect information, we will update this policy, change the date above, and explain the change in the app.
Contact
Questions about privacy: support@markerhunterapp.com