With the Backups section in the server panel you can take a snapshot of your world with one click, and restore any backup with one click too.
Manual backups
A backup contains your worlds, your plugins or mods and your configuration files in a single archive. It can be taken while the server runs: the system flushes the world to disk first, so you never get a half-written copy. Every backup is compressed and integrity-checked.
You can label a backup. One taken before a big change and given a meaningful name is what lets you tell, months later, which snapshot was which.
File Protection
The system takes an automatic backup every day your server is up, keeping only the most recent one and clearing the older ones. Your manual backups are unaffected and are never cleared on their own; you can keep up to 10 at a time.
File Protection is on and free on every server. The only limit is your server's own disk space.
When you change software
When you change server software (from Paper to Fabric, say), all content from the old family is automatically saved into a profile. Return to the same software and your worlds and settings are still there.
Important: before deleting a server
When you permanently delete a server, the backups belonging to it are deleted too. Backups live in storage independent of the machine your server runs on, but they're tied to the server record.
So before deleting, download what you want to keep to your own computer: a snapshot from the Backups section, a world from the Worlds section, or individual files from the Files section. For detail, see the backup guide.