Marvin supports manual backups (web or desktop) and automatic backups (desktop-only).

First, open ☰→Account, then click the Backups tab at the top. Then click the Restore tab in the middle:

Then either drag a .json.lzma backup file into the big box, or click to browse for one.

Your Marvin data comprises of a number of items, including tasks, projects, events, time blocks, settings, etc. Items that have been changed or deleted since you created the backup will be restored to the values they had at the time of the backup. Any items you created since you took the backup will remain after restoring the backup. In other words, backup restoration is additive!

The source of truth for time tracking data is on our server and isn't backed up with your data. Therefore it isn't possible to restore this data. But there is a local copy of your time track data saved with your tasks when you backup, so you could always extract this data for use elsewhere.