Libre 3 sample iOS client

Stock-iPhone Swift app that drives the Libre 3 BLE handshake and NFC takeover, delegating native crypto over HTTP to the paired Android shim at poml88/libre3-auth-android-server.

Project status

• To the best of my knowledge, this was the first publicly available open-source solution for Libre 3 BLE connectivity on iOS at the time of writing.
• It is not fully offline, because this app still performs an HTTP request to the paired Android shim during each new BLE handshake.
• In that sense, it is more accurate to describe this approach as “99% offline” rather than 100% offline.
• This implementation may already be superseded by newer work toward a fully offline solution, including the Swift package LibreCRkit, which is being developed by other contributors.

Disclaimer

This is a personal hobby project for research and interoperability. It is not a medical device and is not affiliated with, endorsed by, or connected to Abbott Laboratories, FreeStyle Libre, or any of their subsidiaries or partners. All trademarks are the property of their respective owners.

The code is provided "as is", without warranty of any kind, express or implied. In no event shall the authors or contributors be liable for any claim, damages, or other liability — including but not limited to incorrect glucose readings, missed alarms, sensor damage, account lockout, or any direct, indirect, incidental, or consequential loss — arising from the use of, or inability to use, this software.

Do not use the output of this software to make medical or treatment decisions. Always rely on a regulator-approved reader or the manufacturer's official application for clinical use.

Use at your own risk.

Credits

Built on two prior open-source Libre 3 projects:

• Juggluco — the v1 identity constants in Libre3ResearchMaterial.swift come from Juggluco's ECDHCrypto.java. The Android shim this app talks to loads a native library shipped in Juggluco's APK.
• DiaBLE — the BLE state machine, NFC takeover commands, and packet AES-CCM framing in this app mirror DiaBLE's Libre3.swift.

Setup

1. Stand up the Android shim (see its README).
2. Open libre3AndroidServer.xcodeproj in Xcode, set your signing team, run on a real iPhone with NFC.
3. In the app: enter the shim's base URL (e.g. http://192.168.1.42:8080) and tap Apply and ping /health — expect loaderReady: true.
4. NFC-tap a sensor already activated by Abbott's official Libre 3 app (this client only does takeover, not first-time activation).