You do not need a Google account to back up your Android device. This guide covers several methods to back up contacts, apps, and files locally or to your own server.

Backup with ADB

adb backup -apk -shared -all -f backup.ab

Sync Files via USB

Connect your phone to a computer and copy the contents of /sdcard/ manually using a file manager.

Use Syncthing for Wireless Sync

Install Syncthing on both your phone and computer to continuously sync selected folders without any cloud service.

Backup Contacts

Export contacts as a .vcf file from Contacts > Export and store it on your computer.