How to Backup app data similar to whatsapp

Question

Hi I am trying to implement backup funcationality similar to whatsapp, but when I come across that after reverse engineering whatsapp manifest code. Here are the observations, android:allowBackup="false" which means Its not taking help of default AutoBackup functionality or any backupagent

But under some obeservations, how this backup is working , check below screenshort

And I need to have unlimited storage limit, unlike AutoBackup with <25mb,

ex: currently my whatsapp backup is holding 112mb size

Quickel

You should use Drive SDK: developers.google.com/drive/android/intro WhatsApp backups are not the ones specified in the manifest, but they are done by a lot of code. Moreover, I think that WhatsApp backups show there because of a Google special permission, other apps backups are listed only by clicking the gear in the top-right corner – Jukebox

I was asked this question in a interview – Harriot