Bi-directional communication between Fitbit and Android app

[Barbarey]

I'm trying to develop an app that will enable bi-directional communication between a Fitbit versa and an android app.

Basically I want to send real-time heart rate data to the companion and have the companion send that data to a web server. From here I want to pull that data into an android app who depending on the data will send a message back to the companion to make the Fitbit vibrate.

Is this type of communication possible? If so, do you have any recommendations?

[kozm0naut]

Yes, this should be possible. I would recommend starting with https://dev.fitbit.com/build/guides/communications/

[Gondwana · Accepted solution]

There is a couple of things here that might also help (Accelerometer Fetcher and Android Fitbit Fetcher). The architecture of that system is a bit different to what you're proposing, because the Android app doubles as the server.

Your Fitbit clockface or app will need to be running for this to work, because we can't run stuff in the background on the watch.

[Barbarey]

can the companion retrieve data from the server?

[Gondwana]

Yes. It can either poll the server using fetch() and process the server's response(s), or use a WebSocket.

[Barbarey]

I appreciate all of your help! 

Would you by any chance know of any documentation i could reference to have android app double as a server?

Again, i appreciate all the help!

[Gondwana]

The Android Fitbit Fetcher I mentioned before is a server. Be warned: it's extremely ugly code because my Android is very rusty.