Hi @PBergamini,
This is a great question! (Optimal double opt-in processes in HubSpot are one of my favorite topics.)
Depending on the subscription, HubSpot has the tools for various approaches. The perfect and exact approach depends on the requirements and workflow environment, so I can’t lay out the exact steps, only share the general approaches.
For an optimal setup, a Marketing Hub Professional subscription and the transactional email add-on are needed. Marketing Hub Professional is needed to set up a workflow that delivers a custom double opt-in email, the transactional email add-on for the subscription type of the custom double opt-in email.
In the marketing email editor, you can create different versions of double opt-in emails and create a confirmation link via the link options. (Hyperlinks in marketing emails have different types, subscription links among them.)
With your workflow, you can then branch by preferred language, for example, and deliver double opt-in emails in language variations.
Without the transactional email add-on, this approach is still generally feasible. However, if a contact fully unsubscribes from all emails, they won’t receive a double opt-in email that’s not sent as transactional.
If you’re using the free CRM or Marketing Hub Starter, it’s not possible to accomplish what you’re trying to do.
There are a lot of things to watch out for which are best explained one-to-one and after getting an understanding of the workflow and email landscape in a portal. These revolve around email re-enrollment, suppression and exclusion, smart content on the confirmation page, the double opt-in system settings, making sure the system double opt-in property is maintained correctly, abuse prevention, and reporting.
If you want to discuss this for your portal and set up a meeting to configure this process based on your requirements, feel free to reach out through the meeting link in my signature. I’ve set this process up dozens of times and perfected it over the past couple of years and I can offer efficient implementation/consultation/documentation, including performance reporting.
Best regards