Privacy Policy

Last updated: 28 June 2026

Fathom is a native dive-planning app for macOS and iPhone/iPad, developed by Total Immersion. The macOS and iOS apps are a single product distributed through one App Store listing and share the same design. This policy describes what data the app collects, how it’s used, and how you can control it. It applies to both the macOS and iOS versions.

Summary

• Your dive plans and logbook entries stay in your own accounts. They live on your device and, when you’re signed in to iCloud, sync across your Apple devices through your private iCloud account. Total Immersion never receives this data on its own servers, and it is never sold or shared with anyone.
• The only data that leaves your device for us is anonymized crash and diagnostic reports, sent via Sentry to help us fix bugs. These reports contain no personal identifiers and are used solely for improving app stability.
• Crash reporting is on by default but can be disabled at any time in Settings → Diagnostics.
• Fathom does not use advertising, analytics, tracking SDKs, or any third-party services beyond Sentry.

Data collected

Crash and diagnostic data

When the app crashes or encounters an unexpected error, Fathom may transmit the following to Sentry:

• A stack trace showing where the error occurred
• The operating-system version (macOS or iOS) and the Fathom version
• A high-level breadcrumb trail (e.g. “user opened paywall”, “computed plan”) — no user-typed content
• For decompression-engine errors: anonymized numeric input only (depth in meters, time in minutes, gas oxygen/helium fractions). User-typed values such as custom gas names or dive notes are explicitly stripped before transmission.

Crash reports do not include:

• Your name, email address, Apple ID, or any other personal identifier
• The contents of your dive plans or logbook
• Custom gas names, tank names, dive notes, or other free-text fields you’ve entered
• Any linkage between an IP address and your identity (the Sentry SDK’s beforeSend hook clears the user identifier before transmission)

This data is used solely to diagnose and fix bugs. It is not used for advertising, marketing, tracking, or analytics.

How to disable crash reporting

Open Fathom → Settings → Diagnostics and toggle Send anonymized crash reports off. The setting takes effect at the next launch and persists across launches.

Your dive data and iCloud

Fathom stores the following on your device and, when you’re signed in to iCloud, syncs it across your Apple devices through your own private iCloud account (Apple’s CloudKit and iCloud Key-Value Storage):

• Saved dive plans
• Logbook entries, including dive sites, buddies, tags, and recorded dive profiles
• Custom gas mixes and tank presets
• Application preferences

This data lives on your device and in the private iCloud database tied to your Apple ID. It is your data end to end: Total Immersion has no access to it, cannot see it, and never receives it on our own servers. iCloud sync is performed entirely by Apple and is governed by Apple’s privacy policy. The same private iCloud account is shared between the macOS and iOS apps, which is how your plans and logbook follow you from your Mac to your iPhone and iPad.

If you prefer to keep your data only on the device, you can turn off iCloud for Fathom in iOS Settings → [your name] → iCloud (or System Settings → [your name] → iCloud on macOS), or sign out of iCloud entirely — Fathom keeps working with your data stored locally. You can delete this data by removing the app and its container, and by deleting Fathom’s data from iCloud in your Apple ID settings.

Purchases

In-app purchases are processed by Apple. Because the macOS and iOS apps share one App Store record, a purchase made on one platform unlocks Fathom on the other for the same Apple ID (a Universal Purchase) — you never pay twice.

The optional 14-day free trial is a standard StoreKit introductory offer managed by Apple; Fathom does not record or store your trial dates itself. Fathom does not see your payment details — the app only receives a StoreKit “entitlement” confirming whether your account has paid access. See Apple’s privacy policy for details on how Apple handles purchase data.

Third parties

Fathom uses one third-party service: Sentry (sentry.io), for crash and error reporting. Sentry’s data handling is governed by their privacy policy at sentry.io/privacy/.

Fathom does not integrate any advertising networks, analytics services, social-media SDKs, or other third-party trackers.

Your rights

Because Fathom does not collect data that identifies you, there is typically no personal data for us to access, correct, or delete. You can:

• Disable crash reporting at any time in Settings → Diagnostics.
• Delete all your data by removing the app and its container and deleting Fathom’s data from iCloud in your Apple ID settings.
• Reach us with privacy questions via the issue tracker.

Children’s privacy

Fathom is not directed at children under 13 and does not knowingly collect any data from children.

Changes to this policy

We may update this policy from time to time. Material changes will be reflected in the “Last updated” date at the top of this page. Continued use of the app after a change constitutes acceptance of the updated policy.

Contact

For privacy-related questions, file an issue at github.com/totalimmersion/fathom-support/issues.