This question has been asked in many guises over time,

This question has been asked in many guises over time, and to some extent ignored, but I'll ask it another way.

e-newsletter seems to have a pretty custom subscription service,people have been asking for 'form action' code, so they can get the subscription working from other methods rather than just the shortcode or widget. I have not yet seen an answer.

What I would love to be able to do (as is possible with MailChimp for instance & CF7) is to have a 'tick box' on my contact form to opt-in when making contact. In my particular case my contact form is Gravity Forms, and whilst I can 'hook' code into the submit, without some form of 'API' I'm all a bit stuck.