The handling for this depends if we are operating under GDPR restrictions or not.
Under GDPR restrictions
The way email addresses are handled in this mode should in general already cover only visitors that are subscribed to your newsletter. Just make sure you chose a method to sync opt-outs.
Do note that in this mode it is important that you use the triggered emails booster since that is only way we can capture the email addresses of visitors that are already subscribed (you may also want to consider the Javascript / HTML content option listed here)
Not under GDPR restrictions
In this special mode Barilliance will capture all email addresses as detailed here but will only send emails to subscribed visitors. New subscribers and existing subscribers are handled a bit differently.
New subscribers
We will monitor the relevant checkbox for subscribing (please send us the list and locations of checkboxes we should monitor). If the visitor checks the box they we will consider them as opted-in
Existing Subscribers
We can capture those addresses but can't know if they are subscribed or not. For this purpose please send us your current mailing list, we'll use it to opt-in the emails inside.
Optionally, you can inform us in an automated way on each new subscriber using using the GDPR option for incoming webhooks
Triggered emails booster
The triggered email booster needs to be setup with the Consider collected emails GDPR compliant option
Opt-outs
You will need to choose a method to sync opt-outs.