Double opt-in is a confirmation form for sending online advertising or e-mail newsletters. Since the legislator has stipulated in the Unfair Competition Act (UWG) that the end consumer must give his consent to receive online advertising, the end consumer must confirm that he agrees to receive advertising e-mails, newsletters or short messages.
Double opt-in is a refined confirmation procedure compared to single opt-in, which works with additional confirmation through a second activation email or by clicking on a link. Since with simple opt-in users can be signed up for a newsletter without their own knowledge, double opt-in represents a security measure against incorrect entries or against misuse.
With this method, an e-mail is sent to the contact details with which the confirming party reconfirms the future receipt of advertising measures. Alternatively, the activation of links is used. If the interested party haschecked his details and activates the link by clicking on it, double opt-in is fulfilled.