Much of the data on your Android phone or tablet is backed up by Google (or the individual apps you use) automatically, but what is being saved for you, and what do you need to save for yourself?

We’ll explain exactly what data is backed up automatically and what isn’t, so you can rest easy knowing your data is safe—or take steps to back up some application data on your own.

WHAT GOOGLE BACKS UP AUTOMATICALLY
Google has a service built into Android, aptly called Android
Backup Service. By default, this service backs up most types of data you care about and associates it with the appropriate Google service, where you can also access it on the web. You can see your Sync settings by heading into Settings >Accounts > Google, then selecting your Gmail address.

Contacts, Email, Docs, and Calendars:
Your Android contacts are synced with your Google contacts online (you can access these contacts from Gmail or on the dedicated Google Contacts page), your email is safely stored in your Gmail account, and calendar events are synced with Google Calendar.

Some System Settings:
Android also synchronizes some system settings—for example, Android stores saved passphrases for Wi-Fi networks and retrieves them on each Android device you use. It also backs up display settings, like brightness and timeout length.

Chrome Browser Data:
If you use the Chrome browser, your bookmarks synchronize with your Chrome sync account. Hangouts Chat Logs: Hangouts chat logs are stored in your Gmail account, assuming you haven’t disabled chat logging in Gmail.

Apps and Other Purchased Content:
Any apps you have purchased (or installed) are linked with your Google account.

When you set up a new Android device (or enter your account
after resetting your Android device to factory default settings ), Android will offer to automatically download and
install the apps you previously had installed. You can also
view apps you have previously installed in the Play Store, so
you won’t forget which apps you have used (or purchased).
Other content you purchase from Google Play is also tied to
your Google account.

Some Third-Party App Data:
Third-party apps often, but not always, sync their data with web services. If you have an app containing data important to you, be sure to check whether it syncs data online before wiping or getting rid of your phone.

Smart Lock Password Data:
If you use Chrome on your computers and have Smart Lock for Passwords enabled, then your saved passwords will not only sync across Chrome on mobile, but also to some apps. For example, if you have your Netflix password saved in Smart Lock for Passwords, it will automatically be available in the app on your Android devices.

Photos:
If you use Google Photos, then you could also back your photos up to Google’s servers. Unlike most of the others
on this list, this feature has to be enabled before it just happens—fortunately, we’ve got you covered on setting that
up, too . There’s also a “Photos Backup” entry in the Backup
& reset menu on Android Nougat.

Uploads:
This isn’t an exhaustive list, but it should give you some idea of what’s backed up automatically. Google includes the most
important things, so you don’t need to worry about losing your email, contacts, apps, saved Wi-Fi passphrases, or even most passwords.


WHAT GOOGLE DOESN'T BACK UP?

Now that we’re covered what Google does automatically back up, let’s take a look at what they don’t:
SMS Messages: Android doesn’t back up your text messages
by default. If having a copy of you text messages is important to you, follow our guide on backing up text messages to your Gmail account.

Google Authenticator Data:
For security reasons, Google doesn’t synchronize your Google Authenticator codes online. If you wipe your Android device, you’ll lose your ability to perform two-factor authentication. You can still authenticate via SMS or a printed authentication code and then set up a new device with new Google Authenticator codes.

Custom Settings, Bluetooth Pairings, and Security Data:
When you set up a new phone or factory reset yours, you’ll have to repair all of your Bluetooth accessories, set up specific settings (like which notifications to block, for example), and re-enter all of your security data, like lock screen passwords and fingerprints.
Make sure, before you reset or sell your phone, that you have any of these items backed up manually if you want them.

THE GRAY AREA OF BACKUPS

Like with most things, there is a gray area here: things that can be backed up, but are also contingent on other variables—like developer integration in third-party apps, for example.

Game Progress:
The Android Backup Service allows developers to back up their data and have it automatically restored in the future. However, you’ll find that some games may not take advantage of this feature. This feature is independent for each game, so do your research before you lose everything upon switching devices or performing a factory reset.

App Settings:
Many other app settings aren’t backed up by default. Whether it’s preferences in an app you use or alarms you’ve created in the Clock app, they probably aren’t backed up online. Some third-party apps contain backup features that export the app’s data to a local file, which you must then keep track of manually (perhaps by uploading it to Google Drive). Again, this is going to be individual for each app.

Again, if there’s anything important you want to keep in one your apps, consult the app’s settings or documentation to figure out whether it backs up automatically or not. In some cases, you may have options to back up your data manually and bring it to your new device in the form of a file.