Dear Mauticians, I want to point you to a little tutorial that I wrote on using our “Mautic DOI Plugin” (in fact we prefer the term “Email Verification”, because DOI is only one use case for this.
In my mind, this is by for the most complete (yet nice and user-friendly) solution to this old problem: Solves immediate sending, multi-brand and -language, configurable redirects, link expiration, follow-up e-mails, … and avoids any need for a “DOI campaign”.
Moreover it introduces three powerful new concepts:
- form actions after confirmation
- skip conditions (“no confirmation needed if ____”)
- form content auditing (for compliance, snapshots what the form stated/asked for, at point of submission)
Enjoy 
Tutorial: How to Implement Double Opt-In in Mautic with the Email Verification and DOI Plugin
Plugin: GitHub - Leuchtfeuer/mautic-DOI-bundle: Universal email verification for Mautic, including Double Opt-In (DOI) · GitHub (Mautic 5 and 7)