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Deliverability Letter

Double Opt-In

Also known as: Confirmed Opt-In, COI

When someone signs up, you send a confirmation email and only add them after they click the link. It adds a small extra step but keeps your list clean and engaged.

Double opt in means someone signs up to your list, then confirms through a follow up email before they get any messages. They add their address in your form, you send a confirmation email, and they only join your list after clicking the link. This extra step makes sure the address is real and that the person actually wants to hear from you.

It matters because it protects your deliverability and your reputation as a sender. People who confirm are more likely to open, click, and stay subscribed. It also helps you avoid spam complaints, fake addresses, and bots that can hurt your sender score.

If you are getting a lot of bad signups or spam complaints, test double opt in on new forms. Start with high risk channels like paid ads or cold traffic. Watch your confirmation rate, spam complaints, and open rates. Keep it where list quality matters more than raw subscriber count.