I'm totally new to Junosphere and the first order of the day is to figure out how to integrate it with some external automation tools. However, I cannot find any reference to an API (suspect there has to be a RESTful API or cmd line of some sort) in the online guides, the datasheets or the community discussion. I must be missing something.
You're absolutely correct - Junosphere is built on RESTful APIs. At this point due to being short-staffed we don't have them properly documented yet. Furthermore, we have a new release in June which will make some modifications to selected APIs.
We will aim to provide at least a primer on the most important APIs (e.g., create users, change passwords, allocate capacity, create/view reservations, start/stop topologies) sometime later in June.