If you are using API to add your subscribers to your leads, you are set to double optin first. That means your subscribers get an email where they need to confirm that they want to receive your email. Now most of the internet marketers recommend to NOT use double optin because most of the subscribers will not confirm your email (for whatever reasons). So it’s best to switch it off.


An example where you would need the API is JVZoo. Let’s say you sell your own product...