Skip to content

Anonymous Telemetry

LoopFollow Anonymous Telemetry

LoopFollow can send a small anonymous report once a day so the maintainers can see which app and iOS versions are still in active use. The data helps make decisions like when it's safe to drop support for older iOS releases. No glucose data, no credentials, no logs leave your device.

This is opt-out: the first time the app comes to the foreground after installing or updating to a version that supports telemetry, you'll see a one-time prompt to choose Yes or No. You can change your mind any time in Settings > General Settings > Diagnostics.

What is sent

A typical check-in looks like this — you can see the exact JSON your own install would send under Settings > General Settings > Diagnostics > What's sent.

Field Example Notes
App version 6.0.7
Build date 2026-04-15
TestFlight or not true / false Whether the install came from TestFlight or a local Xcode build.
Instance LoopFollow / LoopFollow_2 / ... If you have multiple LoopFollow installs side by side, this distinguishes them.
IDFV Apple per-vendor UUID Apple's identifierForVendor — opaque, scoped to LoopFollow's bundle prefix, and resets when all of this developer's apps are removed from the device. Combined with the Instance field above, identifies a specific install.
Device iPhone15,2 Apple's hardware identifier (not the marketing name).
Platform iOS / iPadOS / macCatalyst
iOS version 17.5
Following app Loop / Trio / ... Which closed-loop app LoopFollow is following, if known. Field is omitted when not yet detected.
Uses Dexcom true / false Whether Dexcom Share is configured. No username or password.
Uses Nightscout true / false Whether a Nightscout site is configured. No URL or API token.
Background-refresh method Silent Tune Which background-refresh strategy is selected.
Display units mg/dL / mmol/L
Remote-command type none / Loop APNS / ... Which remote-command path is configured.
Appearance dark / light / system
Calendar / Contact integrations true / false Whether those features are turned on.
Cold launches in past 7 days 12 A count of process restarts; high values can flag stability issues.

The server adds two fields when it stores each report:

  • receivedAt — the time the report was received.
  • dayBucket — a date label (e.g. 2026-04-29) used to deduplicate.

What is not sent

Specifically and explicitly:

  • No glucose values, insulin or carb data, treatments, or any other health data.
  • No Nightscout URL or API token. Only a yes/no flag for whether Nightscout is configured.
  • No Dexcom credentials. Only a yes/no flag for whether Dexcom Share is configured.
  • No time zone.
  • No remote-command secrets, no APNS keys.
  • No GPS or location data.
  • No logs. Logs are never sent automatically. The existing Settings > Logs sharing flow is unchanged and only triggered by you.

The receiving server also does not log your IP address — the NGINX edge zeroes the last octet of IPv4 addresses and only retains the /64 prefix of IPv6 addresses before anything is written to disk.

Where it goes

Reports are sent over HTTPS to https://lf.bjorkert.se/api/telemetry/checkin, which is self-hosted by the maintainer. There is no third-party analytics service involved.

How to opt out

The toggle lives at Settings > General Settings > Diagnostics > Send anonymous usage stats. Turning it off is immediate and persistent.

The Diagnostics section also has:

  • What's sent — renders the exact JSON your install would send right now, with a Copy button if you want to inspect it more closely.
  • Privacy — a shorter in-app version of this page.

How often

A check-in is sent at most once every 24 hours, or once after a new build is installed (whichever fires first). It runs in the background while the app is active or refreshing in the background — LoopFollow schedules the next check-in based on when the last one was actually sent, so a relaunch a few hours after the previous send simply waits out the remainder of the 24 hours.

If a send fails (network error, the server is unreachable, etc.) the last-sent timestamp is not updated, so the next scheduled check tries again.

For the curious

The iOS implementation lives at LoopFollow/Helpers/Telemetry.swift on GitHub. The receiving server is a small .NET service in a private repository on the maintainer's account.