FAQ

Is this an official Tandem or Dexcom product?

No. faBolus is an independent, open-source project — not affiliated with, endorsed by, or a product of Tandem Diabetes Care or Dexcom. It's a manual remote-bolus + status viewer, not an automated closed-loop system.

Is this the Tandem app, or controlX2?

No. It's an independent reimplementation for iOS, inspired by the naming of jwoglom's Android controlX2 and built on the pumpX2 protocol work. Not affiliated with or endorsed by either, nor by Tandem Diabetes Care.

Can I use this to dose insulin?

faBolus is experimental and in development — not FDA-cleared. Use it responsibly, with your clinician, and at your own risk. See Safety.

Which pumps are supported?

Tandem t:slim X2 — and only the t:slim X2. Other Tandem pump models aren't supported in this version; faBolus declines to connect to one and says so rather than trying to talk to it. Support is also pinned to a specific t:slim X2 firmware version that's been tested; the protocol can break on a pump firmware update, so the app is treated as disposable against vendor changes.

Can faBolus get glucose without going through the pump?

Yes — optionally, through Dexcom Share: a cloud-polled feed you can turn on so a reading keeps flowing if the pump-to-sensor link drops. The pump stays the primary source; Share is the only fallback in this version. See Glucose (Dexcom Share).

Can I use faBolus and the official Tandem app (t:connect) at the same time?

You can install both, but the pump pairs to one controller at a time — so only one can be connected at once, and there's no way to keep both paired or switch instantly. The pump never stores two pairings, and the 6-digit code can't be shared between the apps (each app runs its own pairing handshake and derives its own key, so writing the code into both doesn't help). Switching means putting the pump in Pair Device mode, which hands out a new code, and pairing the app you want — which evicts the other. While faBolus stays the paired app it reconnects with no code ("Connect (saved pairing)"); the new-code step only comes up when you bounce between the two. See Pairing your pump.

faBolus is not a full replacement for the official app. Some pump settings and configuration can only be changed in t:connect; faBolus doesn't support them yet. A common setup: use faBolus day-to-day for monitoring and remote bolus, and when you need an official-app-only setting, pair t:connect, make the change, then re-pair faBolus. See Pairing your pump.

Do I need to be a programmer to build it?

No. The build guide walks through every step in plain language — get an Apple account, install Xcode, and run the app on your iPhone.

Do I need to pay Apple?

Not necessarily. A free Apple ID works but the app expires after 7 days; the paid Apple Developer Program ($99/yr) lasts a year and makes the widgets more reliable. See Apple ID & Developer account.

Does the Garmin talk to the pump directly?

No. The iPhone owns the connection; the Garmin remote lives in the separate faBolusGarmin repo and always relays through the phone.

Can I bolus by carbs?

Yes. Enter carbs (and optionally BG) and the app uses the pump's own calculator — carb ratio, correction factor (ISF), target, and IOB — to recommend a dose you then confirm. Entering units directly is always available too. See Bolus & cancel.

How do you know the protocol bytes are right?

Every outgoing message is tested byte-for-byte against the pumpX2 cliparser oracle, in CI, on every push.