Field selection for token economy: an explicit list of field names to include in the response, or ["*"] for every field. Omit for this endpoint's own default field set.

Category tag public IDs (cat_…) to associate with this event.

Properties this event carries — fully replaces the existing set. Each entry is either { id } (an existing property public_id of the application) or { name, data_type, position? } (links the application's property with that name, or declares it; data_type is required and must match). A property is shared by every event of the application: it is renamed, retyped or deleted through the custom event properties endpoints. data_type must be one of: int, bool, float, string, date, array_of_strings.