Overview

This guide does not substitute reading Google Documentation:

Google Play Help

What is an .aab?

It's a file format with all the necessary resources to generate optimized APKs.

In a practical manner this is the new format that you need to use to submit an app to Google.

Read here for more detailed explanation: https://developer.android.com/guide/app-bundle

One file format two options:

Option A - AAB signed by Google

Let Google generate an app signing key (recommended).

More than 90% of new apps use Google-generated app signing keys Protects against loss or compromise (the key is not downloadable).

Download distribution APKs signed with the Google-generated key for other distribution channels, or use a different key for them.

Option B - AAB with my own key

Choose your own app signing key.

Keep a local copy of the key for increased flexibility.

Use the key you're already using (for example, if your app is pre-installed).

Increased security risk if local copy is compromised.