Support

Last updated: 2026-05-11

cairn is an iOS app and command-line tool that reconciles your iPhone photo library against an Immich server you run or control. When you delete a photo on your phone, cairn moves the matching asset on your Immich server to its Trash.

This page is the support resource for the iOS app.

Get help

Email cairn-ios@proton.me for support, bug reports, or feature requests. Include:

  • the build number you’re running (Settings → About)
  • your iOS version
  • a short description of what you tried and what happened

Replies typically come within a few days.

Common questions

Where do I get an Immich server?

cairn is a companion to a self-hosted Immich server. If you don’t already run one, start with the official Immich getting-started guide. cairn is not affiliated with Immich.

What happens when I delete a photo on my iPhone?

  1. iOS reports the deletion to cairn through its public PhotoKit change-log API.
  2. On the next sync, cairn checks whether the photo also exists on your Immich server (matched by SHA1 hash).
  3. If it does, the matching asset is moved to your server’s Trash — not hard-deleted. You have 30 days to restore it from Immich’s own Trash view.

How do I undo a sync?

Every sync run is tagged on Immich with cairn/v1/run/<id>. To undo, open cairn → Runs → tap the run → Restore. The assets move back out of Immich’s Trash into your active library.

cairn says “Couldn’t reach Immich” — what now?

The server is unreachable (offline, wrong URL, VPN dropped, certificate expired). cairn doesn’t lose any work — your decisions are queued and replayed when the connection returns. If you’re sure the server is online, double-check the URL in Settings → Connection.

Why does cairn need Full Photos access?

To detect deletions and compute SHA1 hashes that match the ones your Immich server stores. cairn reads photo bytes only long enough to compute the hash, then discards them — they never leave your device. See the privacy policy for the full data flow.

How do I delete cairn and its data?

Uninstalling the app removes all on-device data (credentials, hash cache, journal, settings). Photos on your Immich server are untouched.

Source code

cairn is open source under the MIT license. The repository lives at github.com/glarue/cairn. A GitHub account is not required for support — please email instead.

Privacy

See the privacy policy for what cairn does and doesn’t do with your data.