Documenting the schema for JSON payloads

[tmcdos]

In REST APIs the information between client and server (in both directions) is transferred as JSON. But currently there is no way to document the data types of the items, whether some of them are optional or mandatory, are there default values, whether there are inter-dependencies between the fields/items, etc.
The only thing that can be documented are different examples of the payloads, presented as something whole.
It would be nice to see some functionality like the functionality in StopLight studio.