Add Mailchimp API into HTML Page (Single Opt in)

I require Mailchimp being added to my website, it currently uses the normal Mailchimp code, however this only allows double opt in. If the website makes use of the Mailchimps API, emails can be added instantly. My Website is: [login to view URL] After an email has been submitted, users should be forwarded to my CPA page (this should be able to be edited so i can change the offer whenever i choose to) PLEASE TEST MY WEBSITE SO YOU UNDERSTAND THE FLOW