Master JSON is used to build a filter based on conditions and retrieve attendees which are qualified conditions.
in master JSON there are three keys profile, register and Engagement which contain objects.

Here is a list of keys and possible values.

Field Name	Possible Values	Description
Label	Any Text	this is used for display text at Front-end side.
columns	List	List of columns which are available in particular filter type.
name	Any Text	name is mapped with table column name. so we can filter that column value with given text.
api	boolean	if it's true then call reference API to suggest possible values.
operator	text, numeric, textWithRef, enum	it is used to map logical operator.
datatype	String, number	datatype of a specific column name.
limit	numeric value	if API is true then we can specify limit for retrieve reference data.
fieldType	scaler, instance	scalar means it's contain single value. instance means it's contain JSON object in a field(column)

Here are the possible error messages, which return if any condition gets failed or required data is missing for processing.

Error code	Error Description
400	The request could not be understood by the server due to malformed syntax.
401	{ "errorMessage": "Not authorized", "errorCode": "4010101", "developerMessage": "Not authorize to access" }
403	{ "errorMessage": "Not Event Host", "errorCode": "4030201", "developerMessage": "Not Event Host" }
404	The resource you were trying to reach is not found.