What Is the Definition of Double Opt-In?

Learn what double opt-in is and how it works for email subscribers

All Worlds Fair Passport Control
All Worlds Fair Passport Control. Orin Zebest/CC BY 2.0 license

With double opt-in, not only has a user subscribed to a newsletter, mailing list or other email marketing messages by explicit request but he or she also confirmed the email address is their own in the process.

How Double Opt-In Works

Typically, a visitor to a website that offers a newsletter will insert their email address in a form and click a button to subscribe. This is their first opting in.

The site then sends a one-time confirmation email to the address entered asking the user to, in turn, confirm the email address. The new subscriber follows a link in the email or replies to the message. This is the second opt-in.

Only after this confirmation is the address added to the newsletter, mailing list or marketing distribution list.

The initial opt-in can also happen by an email sent to a subscription address; since email addresses are easily forged—the address in the From: line is not usually verified—double opt-in is still useful and necessary to confirm both the email address and the user's intent.

Why Use Double Opt-In? Advantages for Subscribers

The twice confirmatory process of double opt-in eliminates the chance of abuse where somebody submits somebody else's email address without their knowledge and against their will.

At the same time, simple mistypes of email addresses are also caught.

The wrongly typed address will not be added to the list automatically, and the user who did want to sign up but made a typo possibly will try to subscribe again—this time, it is to be hoped, with the correct address.

Why Use Double Opt-In? Advantages for List Owners and Marketers

Since only people who do want to be on a list end up on it,

  • messages are more targeted and
  • conversation rates should be higher with
  • lower unsubscription rates.

Double opt-in also guards against accusations of spamming, say by forgetful users or by malicious competitors.

When the latter report you to a DNS blacklist for blocking, you have proof of not only initial sign-up on the website but confirmation through the email address. Do keep records of the whole process, of course, complete with timestamps and IP addresses.

Why Not Use Double Opt-In? Disadvantages for Subscribers and List Owners

The downside to double opt-in, obviously, is that some people who enter their email address will not follow through and end up not subscribed. The confirmation email may also end up in the user’s “Spam” folder (when the actual list messages would not) or not be delivered altogether.

The challenge, then, is to make the list and the process engaging enough for readers to follow through with their subscription request.

For subscribers, the chief disadvantage is to their time: they do have to open an email and, typically, follow a link in addition to entering their email address in a form.