Collins from MailOptin here. MailOptin has long had an integration with CC. See https://marketplace.constantcontact.com/Listing/applications/mailoptin/PML-77364
We always have to create a new account anytime we want to investigate an issue, fix a bug or add new feature.
Can you please create a CC account for us that never expires?
We integrate with dozens of other email marketing software and they've always provided us with a test account.
Looks like you are already working with your account manager. If you have any other questions let us know.
View API documentation, code samples, get your API key.