I need to add an email address to a Constant Contact account from a PHP form processor as a secondary action, not the main purpose. It needs to be associated with an autoresponder that sends an automatic follow-up the next day.
Which API should I use? I see the code samples for PHP, but it's not clear to me which API they use. I think I want the Site Visitor API so I can add them to the autoresponder without a welcome email. Is there a sample on doing that in PHP?
Also, I see that I need to know the 'list number' to add them. How do I find that number for a given autoresponder?