Ægir Prediction Privacy Policy

Ægir Prediction is an app for underwater acoustic propagation prediction, running on iPadOS, iOS and macOS. This policy describes — in plain language — what data the app collects, what it transmits, and what it doesn't.

What we don't collect

• No account or sign-in is required. The app does not ask for your email, name, or any other identifier. There is nothing to "create an account" for.
• No analytics, no telemetry, no usage tracking. The app contains no analytics SDKs (Google Analytics, Mixpanel, Firebase Analytics, etc.).
• No advertising. The app contains no advertising SDKs, no ad networks, no third-party advertising identifiers.
• No cross-app tracking. The app does not request App Tracking Transparency permission and does not access the IDFA (Identifier for Advertisers).
• No personal information. The app does not access your contacts, photo library, microphone, camera, location, calendar, or any other personal data source.

This is reflected in the app's PrivacyInfo.xcprivacy manifest, which Apple uses to generate the public "Data Not Collected" label on the App Store listing.

What stays on your device

The app stores the following data locally on your device only, in UserDefaults and the app sandbox. None of this leaves your device unless you explicitly export it (e.g., via the Diagnostics export feature):

• Your last-used scenario state — pin coordinates, source/target depth, frequency, propagation mode, display preferences (depth in feet vs metres, range in nautical miles vs kilometres, lat/lon in DMS vs decimal, etc.).
• The list of regional data packs you have downloaded.
• App-internal logs used for crash diagnostics, retained only for the lifetime of an app session unless you actively export them via Settings → Diagnostics.

What the app does send over the network

The app makes network requests in three specific cases. In every case, the request transmits only what is needed to perform the requested action; no personal identifier is included.

• Downloading optional regional data packs. If you tap "Buy" or "Download" on a regional data pack in Settings, the app fetches the pack file from packs.aegirprediction.app. The request is a standard HTTPS GET; the server logs the request URL, your IP address (as standard for any HTTPS request), and an HTTP User-Agent string. We do not link these logs to any identifier of yours.
• Fetching optional live ocean conditions. If you enable a live-data toggle in Settings, the app fetches up-to-date temperature and salinity profiles from hycom.aegirprediction.app, and live wind and wave conditions from weather.aegirprediction.app, for your current pin location. Both are self-hosted services we operate; they serve public-domain ocean and weather model data (HYCOM, NOAA GFS / GFS-Wave). Each request transmits only the pin coordinates.
• App Store / TestFlight services. All in-app purchases are processed by Apple via the App Store. We never see your payment details, your Apple ID, or your billing address — Apple handles the entire transaction and only tells us, via the StoreKit API, that "this purchase succeeded" (so the app can unlock the corresponding data pack). All crash reports are also routed through Apple's standard TestFlight / App Store crash-reporting infrastructure, which is governed by Apple's own privacy policy, not ours.

How the live-data services keep your data safe

packs.aegirprediction.app, hycom.aegirprediction.app and weather.aegirprediction.app are hosted on a personal NAS at the founder's residence, fronted by a Cloudflare Tunnel for TLS termination and DDoS protection. Server logs are retained only for the time needed to debug operational issues (typically less than 30 days) and are never shared with any third party. The services do not require, ask for, or accept any user account.

In-app purchases

The app offers optional in-app purchases for higher-resolution regional data packs. All purchases are processed by Apple via the App Store and are subject to Apple's terms. We do not see, collect, store, or process your payment details. Apple tells us via the StoreKit API only the product identifiers you have purchased so that the app can unlock the corresponding content on your devices that share the same Apple ID (including Family Sharing where applicable).

You can restore previously-purchased packs on a new device by tapping "Restore Purchases" in Settings; this is a standard Apple-provided flow and transmits nothing to us.

Data we share with third parties

None. The app does not transmit user data to any third party for any reason. The only "third parties" involved are:

• Apple — handles app distribution, App Store / TestFlight, crash reporting, and in-app purchases. Governed by Apple's privacy policy.
• Cloudflare — provides the TLS-termination and Tunnel that fronts packs.aegirprediction.app, hycom.aegirprediction.app and weather.aegirprediction.app. Cloudflare sees the standard HTTPS request metadata (URL, IP, User-Agent) and is subject to Cloudflare's privacy policy.

None of these parties is provided with any user-identifying data by us — they see only the standard metadata that any HTTPS request to any internet service produces.

Children's privacy

The app does not knowingly collect any data from anyone. Since no data is collected, no special rules apply to children's data — there is no children's data because there is no data.

Changes to this policy

If the app ever changes to collect, transmit, or share user data in a way not already disclosed above, this policy will be updated before that change ships and the new disclosure will be visible in this policy and in the App Store privacy labels for the relevant app version. Material changes will also be communicated through the app's release notes.

Contact

Questions, concerns, or requests about privacy can be sent to [email protected]. We will respond personally.