Need an opt in form with email Match validation (2 required email fields)

I really am hoping that Keap can add this feature.
It is forcing us to look outside of Keap for this solution, but that doesn’t work well either, as it doesn’t send a double opt in link to show engagement. And there are other issues. Seems our “free whitepapers” just get downloaded even if the contact has previously opted out of all emails… if we go with an outside resource for this email matching verification.
Our Keap Partner suggested Formidable Forms + Zapier, but I see it’s now showing all these people that are downloading our “free stuff” as unengaged. And if I try to deliver the “free whitepaper” back through a campaign, it doesn’t even send if they’ve ever opted out in the past, and clearly they want to engage again, but can’t.
Does anyone know of a way to get the formidable form to send a double opt in to help deliver the “free whitepapers”?

You can’t opt someone back in via the API, so if they opted out of your system in the past, you would need to have them go to a Keap web form and sign up again.

My recommendation, if you are using a 3rd party, is to have them request your info, send them into Keap. If they have an ‘opt out’ status, through a 3rd party, send them an email saying that it appears that they previously requested an opt-out of your system, so you want to be sure that it’s them requesting info, and then send them to a link to a web form where they re-enter their email and say ‘yes, I want to get this info’. That will opt them back into Keap and you can then deliver them the double-opt in link and your materials.