Here is the description of response attributes, which returns in the form of JSON.
It returns unique integer value which returns after successful registration of order.
Here is the possible error messages, which return if any condition gets failed or required data is missing for processing.
No Event could be found
You can not purchase addons ticket without purchase event ticket.
Order ticket count is zero.
Number of selected seats must be same as number of tickets.
Sorry, there are only "ticket_count" tickets available at this price.
Ticket type id "ticket_type_id" is not valid for event.