A text property can contain JSON. The API treats changes to this type of property as any text. If the field is tagged RESTAPI_JSON on the other hand, it will be necessary to pass a valid JSON as the value to assign to the property.
The RESTAPI_JSON tag can be specific:
RESTAPI_JSON/OBJECT : the JSON must be an object
RESTAPI_JSON/ARRAY : the JSON must be an array
The value to be assigned can be directly indicated in JSON, or as a string that represents JSON.
Examples:
{
"property": {
"a": 1,
"b": 2,
"c": 3
}
}
{
"property": "\"property\": {\r\n \"a\": 1,\r\n \"b\": 2,\r\n \"c\": 3\r\n}"
}