We are ideally looking for a solution with an API that will allow us to trigger an email survey based on an event in our 3rd party software (in this case, closing a customer ticket.) Is this possible with Constant contact?
If you are using the API, as with the regular user interface, the only way to trigger a one off email to a customer is through the autoresponder. Which is activated only when a customer is newly added to the account into an autoresponder list. So while it might be possible to trigger this when a customer closes a ticket, I am not sure how realistic it would be to implement.