Safety¶
Experimental software — you assume all responsibility
faBolus is an independent, open-source project in development for experimental use. It can command an insulin pump to deliver insulin, and it is not FDA-cleared or otherwise approved. It is provided as-is, with no warranty; if you build, install, or use it, you take full responsibility for what it does. Work with your own clinician and use your own judgment.
How faBolus is built for safety¶
Several checks are built in so a bolus can't happen by accident:
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Max-units clamp
Every bolus is capped at your pump's configured maximum, and the pump enforces its own limit independently.
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Explicit confirmation
Delivery always requires a deliberate confirmation: the Quick Bolus widget and the Garmin Venu 3S both use the same sequential 1-2-3 tap. (Button-only Garmin watches use a two-button hold instead, but that hardware isn't part of this build — it lives on
experimental.) -
Signed commands
Every insulin-affecting command is cryptographically signed; the pump rejects anything that isn't. faBolus never modifies pump firmware — it only speaks the existing Bluetooth protocol.
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Cancel any time
A bolus can be cancelled mid-delivery, and faBolus reports the amount actually delivered.
One connection at a time
The pump accepts a single control connection, so while faBolus is paired the official Tandem app cannot be, and vice versa.
Validation¶
Every change that can affect delivery is put through the same checks before it's trusted:
| Check | What it proves |
|---|---|
| Protocol parity | Outgoing messages byte-match the pumpX2 cliparser reference. |
| Delivery accuracy | Requested units match the amount actually delivered. |
| Signature enforcement | Malformed / incorrectly-signed requests are rejected. |
| Cancel | A mid-delivery cancel stops the pump and reports partial delivery. |
| Interruption | App kill / Bluetooth drop mid-bolus fails safe. |
| Connection handoff | Switching control between apps never leaves an ambiguous state. |
| Soak | Multi-hour stability; reconnect after suspend. |
Independent project
faBolus is not affiliated with, endorsed by, or a product of Tandem Diabetes Care or Dexcom. See the FAQ.