Fields that are allowed to be used
The value of the field should be In database. We do not expose calculated fields. Also, the field should be In use and In selection. You can find these settings in Field definer.
Fields that hold passwords and a date-time period are not exposed.
There are more detailed rules on where exactly fields can be used in the body of the request.
For example, if a field is read-only, you cannot use it in the Values section, where the to-be-updated values are listed. More about this can be found in the section on the OpenAPI document.