Gas Check — Privacy Policy

Effective: 16 October 2026 · Last updated: 16 October 2026

The short version. Gas Check uses your location to rank nearby fuel stations, and your location is never sent to us. The app downloads the whole national price list and does the ranking on your phone, so our server is never told where you are or which station you chose.

The map is Google Maps, so Google receives the part of the map you are looking at, as any online map would. There is no account and no sign-up, and we run no analytics or crash-reporting service. One advertising banner is served by Google AdMob, and a Google security check (Firebase App Check) confirms that requests to our server come from the genuine app.

1. Who is responsible

Gas Check is an independent app published by Karmakai, which is the data controller for the purposes of the EU General Data Protection Regulation (GDPR).

Contact: privacy@karmakai.pt

2. Your location

With your permission, Gas Check reads your device's precise location while the app is open. It is never read in the background.

Your location is used on your device, to:

centre the map on where you are and show your position on it;
measure the distance to each station;
compute the effective price (the pump price plus the fuel burned driving there and back) and rank the results.

Your location is not sent to us, and not sent with any request for fuel prices. This follows from how the app is built: it downloads the complete price list for your country and filters it locally, rather than asking a server "what is near this coordinate?". Our server therefore never receives a coordinate at all.

The map in the app is provided by Google Maps. To draw your position as a blue dot, Google's map component on your phone uses your device's location, and Google receives the area of the map you are viewing. Section 4 explains what Google receives and under which terms.

Location access is optional. Without it you can browse the map and see the stations in the area you choose. You can withdraw location access at any time in your device settings.

3. What leaves your device

Connection	What the recipient receives	Why
Fuel price data `data.gascheckapp.com`	Your IP address, the time of the request, the app's version and platform (Android or iOS), and an App Check token (see §6). No location, and nothing that identifies you or your device.	To download the current price lists for Portugal (from DGEG) and Spain (from MITECO) and the app's own settings, such as whether an update is needed. This server is operated by us and runs on Cloudflare.
Map Google Maps	Your IP address, the map area you view and how you pan and zoom it, your device model and operating system version, crash reports from the map component, and an identifier Google uses to count daily map users. See §4.	To draw the map.
App integrity check Firebase App Check (Google), with Google Play Integrity on Android and Apple App Attest on iOS	Information about the app (name, version, signing certificate) and a device attestation produced by Google Play services or by Apple, plus your device model, operating system version and the store the app was installed from. See §6.	To let our server tell the genuine app apart from automated scrapers and abuse.
Advertising Google AdMob	Advertising ID, IP address, device and ad-interaction data. See §5.	To serve the single banner that funds the app's running costs.
Navigation hand-off Google Maps, Apple Maps, Waze, or your chosen map app	The coordinates of the station you selected, only when you tap "Directions".	To start turn-by-turn navigation. That app's own privacy policy then applies.

An IP address is sent with any internet request and is, in principle, personal data. Cloudflare, which hosts our server, keeps request logs for up to 7 days. They can include your IP address, the approximate location derived from it, the app version and platform, and the address requested. We use them only to troubleshoot and secure the service. Beyond that we keep daily totals, such as the number of requests per platform, which contain no IP addresses or identifiers. None of this is linked to any user, used to build profiles, or shared.

Versions of Gas Check released before 1.1.0 also connected to sedeaplicaciones.minetur.gob.es for Spanish prices and to tile.openstreetmap.org for map tiles. Those servers received your IP address and, for map tiles, the approximate area you were viewing, under the OpenStreetMap Foundation's privacy policy.

4. Google Maps

Gas Check includes Google Maps features and content. Your use of them is subject to the then-current versions of the Google Maps/Google Earth Additional Terms of Service and the Google Privacy Policy.

When the map is shown, Google's map component sends Google your IP address, the map area you are viewing, how you move the map, details about your device and the component itself, crash reports, and a pseudonymous identifier Google uses to count daily map users. When the map shows your position, the component uses your device's location on your phone to draw it. Google states that its maps services may collect location coordinates and IP addresses and uses this data to provide and improve its services, under the Google Privacy Policy.

You do not need a Google account, and we do not receive any of this data. We see only the total number of map loads in our Google Cloud account.

5. Advertising

Gas Check displays one banner, at the foot of the list of stations, served by Google AdMob. There are no interstitials, no video, and no ads anywhere else in the app.

Consent in the EEA, the UK and Switzerland

The first time the list of stations is shown, Google's consent form asks whether you agree to personalised advertising. Your choice is stored on the device and honoured on every later visit; you are not asked again.

If you consent, Google may use your advertising ID and related data to personalise ads. Legal basis: your consent (GDPR Art. 6(1)(a)).
If you decline, AdMob serves limited ads, which do not read or write identifiers on your device for advertising purposes. The banner still appears; only its targeting changes.

You can change your answer at any time by clearing the app's storage in your device settings or by reinstalling the app. Google's consent form then asks again.

Gas Check does not ask for App Tracking Transparency permission on iOS, so iOS ads are not personalised using the IDFA.

What Google does with this data is governed by Google's Privacy Policy and Google's advertising terms. We receive only aggregate revenue totals, never any data about individual users.

6. App integrity checks

Our price server uses Google's Firebase App Check to confirm that requests come from the genuine Gas Check app, which protects the service from automated scraping and abuse.

On Android, Google Play services produces an integrity attestation through the Play Integrity API. It covers the app (package name, version, signing certificate), whether it was obtained from Google Play, and whether the device passes Google's integrity checks.
On iOS, Apple's App Attest service produces an equivalent attestation for the app on your device.

Firebase checks the attestation and gives the app a short-lived token, which travels with requests to our server. The token identifies the app, not you or your device. Firebase also receives your device model, operating system version and the store the app was installed from, which Google uses to measure platform and version adoption and does not link to any user or device identifier. Google's terms prohibit using Play Integrity to track individual users or devices, and Google deletes this data after a fixed retention period.

The App Check library also contains Google's reCAPTCHA Enterprise component. Gas Check never switches it on.

7. What is stored on your device

All of the following stays on your phone. None of it is transmitted to us, and all of it is deleted when you uninstall the app.

Your settings: fuel type, consumption in L/100 km, tank size, search radius, language and light or dark theme.
Your saved stations: the identifiers and names of the stations you save.
A cached copy of the price list for each country you have viewed, so the app works on a poor connection. Prices more than 48 hours old are still shown, with a warning, until fresh ones arrive.
App state: whether you have completed the introduction, the app settings last received from our server, and whether you dismissed an update reminder.
Advertising diagnostics: a count of consecutive failed ad loads, used to pause the banner if ads stop loading. No identifiers.
Your advertising consent choice, stored by Google's consent SDK.
A short-lived App Check token, kept by Google's Firebase SDK, and map data cached by Google Maps.

8. What Gas Check does not do

No user accounts, sign-up, email address, or password.
No analytics or crash-reporting service of our own. The Google components described above collect their own diagnostics, as explained there.
No background or continuous location access.
No selling or sharing of personal data. We hold no personal data to sell.
No advertising from fuel retailers or competing fuel-price apps, so the ranking cannot be influenced by an advertiser.

9. Legal bases under the GDPR

Processing	Legal basis
Reading your location on the device	Consent, the permission you grant to the app (Art. 6(1)(a)). The data never reaches us.
Request logs and daily totals on our server	Legitimate interests: operating and securing the service and knowing which app versions are in use (Art. 6(1)(f)).
App integrity checks	Legitimate interests: protecting the service from scraping and abuse (Art. 6(1)(f)).
Showing the map with Google Maps	Legitimate interests: providing the map you use to find stations (Art. 6(1)(f)).
Personalised advertising	Consent, collected via Google's consent form (Art. 6(1)(a)).
Limited (non-personalised) advertising	Legitimate interests: funding a free app, without device identifiers (Art. 6(1)(f)).

10. Where data is processed

Cloudflare and Google may process the data described above outside the European Economic Area, including in the United States. Both rely on the EU–US Data Privacy Framework and the European Commission's standard contractual clauses for these transfers. Apple processes App Attest data under its own privacy policy.

11. Retention

We do not hold personal data about you beyond the server request logs, which Cloudflare deletes after at most 7 days. The daily totals we keep contain no personal data. On-device data persists until you uninstall the app or clear its storage. Data held by Google in connection with maps, advertising and integrity checks is retained according to Google's own policies.

12. Your rights

If you are in the EEA or the UK, you have the right to access, rectify, erase, restrict, and object to the processing of your personal data, and the right to data portability.

In practice these rights have little to act on here: Gas Check has no accounts, and the only trace of your use on our systems is short-lived request logs that are not linked to anyone. Uninstalling the app erases everything it has kept on your phone. For data held by Google, please use your Google Account controls or Google's privacy policy.

You may contact us at privacy@karmakai.pt with any request or question. You also have the right to lodge a complaint with your national supervisory authority: in Portugal, the CNPD; in Spain, the AEPD.

13. Children

Gas Check is intended for drivers and is not directed at children. We do not knowingly collect personal data from children.

14. Accuracy of fuel prices

Not a privacy matter, but worth stating: prices come from official government open-data services and may be out of date or incorrect at the pump. Gas Check shows when the prices it holds were published and warns you when they are more than 48 hours old. Always check the price displayed at the station.

15. Changes to this policy

If this policy changes materially, for example if a new data source or a new third-party service is added, the "last updated" date above will change, and significant changes will be announced in the app's release notes. The current version always lives at this address.

16. Contact

Karmakai
privacy@karmakai.pt