The JetBackup software itself is licensed by a public server IP address and covers all accounts on the server for $8.95/mo or $89.95/year. If you have 2 servers, 1 license would be required for each server.
In order to INSTANTLY activate your JetApps license, and properly capture your server's information, please submit your order online at https://www.jetapps.com/buy-now
Orders are INSTANTLY processed, and your license will be activated. You will receive an email detailing the next steps in the activation process, including how to install your license. Orders are submitted securely using 128-bit SSL encryption.
JetBackup - https://docs.jetbackup.com/manual/whm/index.html