I have the following use case:

An external company (the one distributing participant links) needs a quote monitor that can read, in real time, how many participants have already been assigned to which treatment quota.
In my oTree project, this information is stored in SESSION_FIELDS.

Question:
Is there any official way to access values from SESSION_FIELDS through the REST API?
Or is the only option to implement a custom API endpoint to expose these values?

Thanks.