What is double opt-in (for GDPR)?

A double opt-in is a confirmation of a subscriber’s wish to receive your emails.

To obtain the subscriber's confirmation: 

• Send an email to the subscribed email address
• In the subject of the email, explain that the subscriber must visit a link to permit you to send them marketing emails

If the subscriber visits the link, then they are 'double opted' in, which confirms that they have agreed to receive marketing emails. This ensures that you can legally send your marketing emails to the subscriber.