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If your API is scripted to send the contact information as COI (customer opt-in) then the confirmed opt-in email will be sent. For more advanced troubleshooting and API specific assistance I strongly advise sending an email to webservices(at)constantcontact(dot)com. This will get you in contact with Constant Contact API specialists. You are also welcome to visit the developer resource site found here. I hope that this was helpful!
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