Double opt-in occurs when a user signs up for an email list and then receives an email with a confirmation link to click to confirm they wish to subscribe.

Only after clicking the link will the user be added to the email list. Double-opt-in can also be known as a "confirmed opt-in" or a "verified subscriber".

Why is double-opt-in important?

By using double opt-in, you greatly reduce the chance of bot and spam email addresses making their way into your audience. Bots (hopefully) won't make it past this step, meaning you can be more confident the subscribers on your list are actual people who wish to receive your emails. This in turn helps to protect your sender reputation and helps you avoid being marked as spam.

Double opt-in also shows the subscriber has a higher level of interest because they need to take an extra step to confirm they wish to receive emails. This can lead to greater engagement and better results for your email marketing efforts.

Can double opt-in lose me subscribers?

A concern many marketers have with enabling double opt-in is losing subscribers.

By adding any extra steps, you risk losing the motivation of the subscriber — putting up too many barriers between their intent and being able to complete their task.

The reality is, if someone isn't willing to take the extra simple step to confirm their email address, they likely weren't that interested in receiving your emails in the first place.

While you may lose a small number of potential subscribers, you make up for this loss by reducing the number of spam complaints and increasing the engagement of your audience.

Double opt-in is a sure fire way to make your email list more valuable and effective.