Firebase Remote Config: what is the definition of an "app instance" regarding percentile conditions?

Question

When I want to perform an A/B test with "Firebase Remote Configs" I assign 50% of the users a value "GroupA" and the other receives "GroupB" using the percentile condition.

According to the documentation (1) the percentile is assigned once each app instance. When I uninstall an reinstall the app on the same phone (including and clearing the users settings) I would expect that the percentile condition is evaluated again and the user will be in either on of the groups. I assume this since also the FirebaseInstanceId retrieved using FirebaseInstanceId.getInstance().getId() changed when reinstalling the app.

What is the definition of an "app instance" in the context of "Firebase Remote Configs"? And for development and testing purposes can the precentile condition be reset?

Gymkhana

Also been looking for this. I've been trying hacks like clearing Google Play Services data, or changing the android id value on an emulator with adb shell settings put secure android_id 0123456789abcdef, thinking that might impact the percentile of my device. But I haven't found any action on the device that seems to impact its percentile. – Aitken

Answer 1

And for development and testing purposes can the precentile condition be reset?

In the dialog where you can edit the condition for Remote Config parameters you can specify a key that is used to randomize the user percentile. This key defaults to "DEF". Changing this key to any other string will give you a different mapping from users to user percentile each time which is helpful for testing.

From the docs:

Each app instance is persistently mapped to a random whole or fractional number, according to a key defined in that project. A rule will use the default key (shown as DEF in Firebase console) unless you select or create another key. You can return a rule to using the default key by clearing the Randomize users using this key field. You can use a single key across rules to consistently address the same app instances within given percentage ranges.

Lipid