Cloud sync and cloud backup both store data remotely but serve distinct purposes. Sync (synchronization) continuously mirrors specific files and folders across devices linked to your cloud account, ensuring you have the identical, latest version accessible everywhere immediately. Any change on one device propagates instantly. Cloud backup, however, creates periodic, independent copies (snapshots) of your entire system or selected data at specific points in time, stored securely in the cloud. Its primary goal is disaster recovery and restoring lost or damaged files from the past.

Sync is ideal for active files you need everywhere, like shared documents using Dropbox or Google Drive, ensuring teams always see real-time edits. Backup is essential for comprehensive protection: services like Backblaze or Apple Time Machine save system images and historical versions. Recovering a corrupted file, restoring an overwritten document, or retrieving data after ransomware attack relies on backups, which preserve prior states sync overwrites.

While sync offers accessibility and collaboration, it offers poor protection: file deletion or malware corrupting a file on one device instantly spreads everywhere. Backups provide strong recovery points. However, they often aren't real-time, require manual restore actions, and use more storage. Synced data deletion policies are generally stricter. Backup offers insurance against data loss, sync enables workflow mobility. Most users benefit from employing both.