Privacy Policy — MapStamp
Effective date: October 21, 2026
The short version
MapStamp has no accounts, no sign-up and no server of ours. Your photos and videos stay on your phone and in your own gallery. We never receive them, and we never receive your GPS position or your street address. (Like most apps, our usage statistics show an approximate region, such as the country or city, which Google works out from your IP address. See section 6.)
To draw the stamp, the app sends your location to Google (for the map and the street address) and to the Norwegian weather service MET Norway (for the weather; if it does not answer, Google's weather service instead). When it seals a photo, it sends only a short fingerprint of the file (a 32-byte hash, never the photo) to a time-stamping service. The free version shows ads from Google AdMob, uses Google's Firebase for usage statistics, crash reports and remote settings, and uses Google Play for the one-time Pro purchase. We do not sell your data.
Email hieu.dtvt10@gmail.com with any privacy question.
1. Who we are
MapStamp is developed by the Essenty Dev Team, based in Vietnam. Contact: hieu.dtvt10@gmail.com.
2. What MapStamp does
MapStamp is a camera app. It prints the date, time, location, street address, weather and a small map onto your photos and videos, so they can serve as a record of where and when they were taken. It can also seal a photo: it adds a QR code and, inside the file, a C2PA record, so that anyone can later check that the file still matches the moment it was sealed. You can also turn a photo into a "stamp" in your Stamps collection, kept only on your phone.
3. Your location
The app reads your location on your phone, through Android's location service, only while the camera is open, to write it on the stamp, in the photo's own metadata (EXIF) and on the map. We never receive your GPS position or the street address. If a stamp template does not show your coordinates, the QR code and the EXIF data of that photo do not contain them either. You can refuse the location permission: the camera still works, without location on the stamp.
To fill in the stamp, the app sends your location to the following services. Each request is made directly from your phone to that service; nothing goes through us.
- Google Maps (map image): the map on the stamp, the map of your Stamps places and the small map on a place page are drawn by the Google Maps SDK, which downloads map tiles for the area shown from Google.
- Google Geocoder (street address): Android's built-in Geocoder turns your coordinates into a street address. On most phones Android sends that request to Google.
- MET Norway (weather): the app asks the Norwegian Meteorological
Institute's public weather service (
api.met.no) for the current weather. It does not send your exact position: it sends the centre of the roughly 5 km × 5 km square you are in. If MET Norway does not answer, the app may ask Google's Weather API instead, with the same rounded position.
These services receive your location only to answer that request. Their own policies apply: Google's Privacy Policy and MET Norway's terms of service.
4. Your photos and videos
Photos and videos are saved on your phone, in your gallery. MapStamp never uploads them, to us or to anyone. A photo you share carries what is printed on it and in its metadata (for example the location in its EXIF data, when the stamp shows coordinates). Sharing is always your choice.
4.1 Seals and time-stamps
When the app seals a photo or video, it asks a public time-stamping authority to sign the time.
It sends only a 32-byte hash (a SHA-256 fingerprint that cannot be turned back into the picture),
never the photo, the video or your location. The authority is DigiCert
(timestamp.digicert.com), or FreeTSA (freetsa.org) if DigiCert does not
answer. DigiCert's time-stamp service is reached over plain HTTP; the request carries nothing but that hash, and the
answer is checked by its signature.
4.2 The check page
The QR code on a sealed photo opens the check page at
daohieu91.github.io/v. The data the page needs travels inside the QR
link itself, after the #, which browsers do not send to the server. When you open a photo or video on that
page, it is checked inside your browser; the page uploads nothing, and its security policy blocks it
from sending data anywhere but its own site.
5. Ads
- Google AdMob shows ads in the free version. To choose and measure an ad, Google's Mobile Ads SDK receives your device's Advertising ID, an approximate location derived from your IP address, device and app information, and how you interact with the ad. MapStamp adds nothing of its own to an ad request: no location, no address, no photos. Once you have Pro, the app requests and shows no more ads, and from the next launch it does not start the ad SDK at all. You can reset or delete your Advertising ID in Android Settings. See how Google uses information from apps that use its services.
- Consent: in regions where the law requires it (for example the EEA, the UK and Switzerland), the app uses Google's User Messaging Platform to ask for your consent before any ad is requested. Ads are personalised only if you consent; if you do not, you may still see ads, but they are not personalised. You can change your choice at any time in the app: Settings → Privacy options (ads).
6. Statistics, crash reports and settings (Firebase)
- Firebase Analytics receives app usage events, for example that a photo was taken, which stamp template was used, or that an ad was shown. Every event is checked against a fixed list of allowed fields, and that list contains no location, address, note or file. Firebase also collects standard device information, such as model, Android version, the Advertising ID and app set ID, and an approximate region (country, region and city) that Google derives from your IP address. We see that region in our Analytics reports; it is never your GPS position. Google deletes event-level data linked to an identifier after 2 months; aggregated statistics (for example, totals per country) are kept. Analytics data sharing with Google is limited to technical support: we have turned off sharing for Google's own products and services, for modelling and benchmarking, and with account specialists. Google's support staff can see our Analytics data only if we ask them for help.
- Firebase Crashlytics receives a crash report if the app crashes: the stack trace, device model, Android and app version, plus three tags we set (Android version, free or Pro, and the stamp template). For errors the app catches and reports itself, the error message is removed before sending, because a message could contain a file name. A crash the app does not catch keeps its original message. Reports may also carry short fixed status notes from the app (for example a billing step name), never your data. Google keeps crash reports for 90 days.
- Firebase Remote Config downloads settings we can change without an update, such as how often ads may appear. To fetch them it sends the Firebase installation ID and the Analytics app instance ID (identifiers for this installation of the app, not for you), and basic device information such as country, language, time zone, Android version and app version. It never sends your photos, location or notes.
7. Purchases and reviews
- Google Play Billing: the one-time "Pro" upgrade is sold by Google Play. Google handles the payment; we receive only a confirmation that the purchase exists. We never see your card or payment details.
- Ratings: the app may ask you to rate it using Google Play's in-app review window. Your rating and review go to Google Play, not to us.
8. Stored on your phone, and backup
The app keeps its data in its private storage on your phone: your settings (including the
note, project and author name you type for the stamp, and the logo image you pick), the photo library index, and your
Stamps collection (passport.db, with the stamp images next to it in the app's no-backup storage: the
place codes, dates and small images of the stamps you made). Stamps are kept only on your phone.
If backup is turned on on your phone, Android Auto Backup copies the app's private storage to your Google account backup, so it comes back on a new phone. We cannot read that backup. It includes:
- your settings, including the stamp note, project, author name and logo image;
- the public certificates the app uses for seals (no private keys: those stay in the phone's secure hardware and are never copied);
- settings that Google's components keep for themselves inside the app, such as your ad-consent choice (the consent record from Google's User Messaging Platform) and the Firebase installation ID.
Not backed up: your Stamps collection (the database passport.db and the stamp images), so stamps are
not in Google's backup and do not come back on a new phone; the photo library index, unfinished captures and unsigned copies waiting for a seal, an old map
cache, and everything in the app's no-backup storage: the Pro and reward caches (Google Play restores Pro by itself),
the built-in place data, an install marker, and the list of pending background tasks. Uninstalling the app deletes
everything it stored on the phone; photos
already in your gallery stay there.
9. Permissions and why
- Camera: to take photos and videos.
- Microphone: to record sound with videos.
- Location (precise and approximate): for the stamp, as described in section 3.
- Notifications: to show progress while a video is being stamped.
- Storage (Android 9 and older only): to save photos and videos to your gallery.
- Photo location (Android 16 and newer only): to read the location saved in a photo or video you pick from your gallery, so it can be stamped. It stays on your phone.
- Foreground service: to keep stamping and sealing a video running when you leave the app.
- Network state: to skip the map and weather when you are offline.
- Advertising ID: used by Google AdMob and Firebase Analytics, as described in sections 5 and 6.
10. What we do not do
- We do not sell your data. We have no server and receive no personal data of our own; the services above receive only what is described here.
- No accounts, no sign-up, and no way for us to identify you.
- Your GPS position, street address, notes, photos and videos are never sent to us, and the app never adds them to analytics or crash reports. (Analytics does show us an approximate region derived from your IP address; see section 6.)
11. Children
MapStamp is not directed at children under 13 and is not designed for them. We do not knowingly collect data from children.
12. Your rights and deleting your data
MapStamp has no account and no server of ours, so we hold no data about you that we could look up, correct or delete, and we cannot identify you from an email. What you can do yourself, at any time:
- Delete what the app keeps on your phone: uninstall it, or use Android Settings → Apps → MapStamp → Storage → Clear data. Clearing data also gives the app new Firebase identifiers and asks for ad consent again (where consent is required). Photos already in your gallery are not affected. To remove the Auto Backup copy, delete the app's backup in your Google account settings.
- Reset or delete your Advertising ID: Android Settings → Privacy → Ads (on some phones Settings → Google → Ads). Ads can then no longer be linked to the old ID. Usage statistics stay linked to the app's own instance ID until you clear the app's data or uninstall it.
- Change your ad consent: Settings → Privacy options (ads) in the app.
- Data held by Google: Google deletes Firebase Analytics event-level data linked to an identifier after 2 months (aggregated statistics, such as totals per country, are kept), and Crashlytics crash reports after 90 days. Data Google holds for advertising is covered by Google's Privacy Policy and your Google account's ad settings.
- Ask us: hieu.dtvt10@gmail.com. We will explain what is stored and where, and help you with the steps above; we aim to reply within 7 business days.
If you live in the EU or the UK, you may also complain to your local data protection authority.
13. Changes to this policy
If the app starts sending any new kind of data, this page will be updated before that version is released, and the date at the top will change.