Android ID
Also called: SSAID, Settings.Secure.ANDROID_ID
The Android ID is a 64-bit value Android generates to identify a device to an app. Since Android 8, it is scoped per app signing key rather than being global, so different apps see different values on the same device. It resets on factory reset.
Android exposes the Android ID through Settings.Secure.ANDROID_ID. Before Android 8 it was a single value every installed app could read, which made it a convenient global device identifier — and a privacy problem. Google scoped it: the value is now derived per combination of app signing key, user and device, so two apps from different developers see two different IDs on the same handset.
What it means in practice
- An app can recognise a returning device even after reinstall, because the value survives uninstalling.
- A factory reset generates a new value, which is why a reset genuinely looks like a new device to apps.
- Two apps cannot collude through this identifier alone, since neither sees the other’s value.
Why it still matters for a fleet
Scoped or not, the Android ID must be distinct per device and stable per session. If a provider clones device images without regenerating it, every phone in the batch shares one value from the app’s point of view — the exact correlation that separate devices are meant to prevent. It is one of the values worth verifying when evaluating any cloud phone provider.