I reverse-engineered the Garmin Varia protocol and built an iOS bike computer

So I recently bought a Garmin Varia, and while I was impressed with the hardware, I was pretty underwhelmed by the software.

My first thought was to just use Strava as my bike computer, but it doesn’t integrate with the Varia. I looked at the existing alternatives, but they either lacked features I wanted or locked them behind a subscription.

So I did what any completely reasonable person would do and built my own. The first challenge was figuring out the Bluetooth communication, since the Varia doesn’t behave like a typical Bluetooth device. After decoding the packets it sends and spending a few weeks testing, I finally got a working app that I’ve been using instead of Strava for navigation.

It started as a personal project, but I’m beginning to think other cyclists might actually find it useful.

Right now it includes:

Bike computer dashboard

Turn-by-turn navigation with rerouting

Ride metrics (speed, elevation, distance, etc.)

Garmin Varia integration with real-time vehicle alerts
Automatic uploads to Strava

Import previously saved Strava routes directly into the app

Eventually I’d like to add support for power meters, heart rate monitors, cadence sensors, and other accessories, but even in its current state it’s been a great bike computer for commuting and longer rides.

It’s iOS only for now. Android to come soon if there’s enough interest (since I don’t own an android).

I’m thinking about opening up a small beta. Would anyone here actually be interested in trying it out and giving feedback? If there’s enough interest, I’ll put together a TestFlight build.