Data
You can export the data from your app to keep a local/external copy of the data: Export Records. Right now there isn’t a way to export the data from the entire app or multiple objects at once.
If you’re familiar with APIs, then you could use the Knack API to automatically export the data from your app: docs.knack.com.
Apps
Right now there isn’t an option for creating an external copy of your app’s structure (pages, views, etc). However, you can create a copy of your app in your account as a backup: Copying Apps.
Just keep in mind that there is a limit to the number of apps you can have based on your plan: knack.com/pricing.
Right now there isn't an option for automatically creating app copies.
Knack Backups
We perform regular, automatic backups of your app data and structure. These are available for restores should one ever be needed.
Restores from backups are included in Corporate plans and above. Otherwise, there is a $100/hr charge for restores due to the manual work required.
You can read more about how long we store backups, how often we do backups, how restores work, and more in this article section: Data Retention, Backups and Restore Options.