Snapt has two categories of pricing. Standard and Enterprise.
An upstream refers to any server that sits behind your Snapt load balancer (web servers, app servers etc). On our Standard pricing plans, your license limits you according to how many backends/upstreams you can add. Enterprise licenses are unrestricted in this regard.
*Please note that an upstream and backend is the same
If you have any other questions, please email us at firstname.lastname@example.org