Understanding the concept of opt-in

Understanding the concept of opt-in


When you are involved in email marketing, you should understand the concept of opt-in. Basically, opt-in means the user has opted to receive mailings from you.

There are 2 types of opt-ins, the first is single opt-in and the second is double opt-in. To be an ethical email marketer, you must practice at the very least single opt-in but it is better in the long run to practice double opt-in.

What is single opt-in?

A common example of single opt-in is when you register for an account on a website. The moment you key in your email address and submit the registration form on a website, you are able to use all the facilities on that website without further verification of your identity. By submitting your email address on this website, you are deemed to have to opted-in to receive mailings and so forth.

What is double opt-in?

Double opt-in is basically single opt-in with an additional verification step. If the website above practiced double opt-in, upon submission of your email address via the registration form on the website, you will be sent an email to your registered email address. In this email, you will most likely have to click a verification link to activate your account on that website. Failure to click that link will mean that your account on that website remains inactive and unusable.

What’s good about single opt-in?

  • Less hassle for users to sign up and they get their account up and running on your website quickly.
  • Mailing list will grow faster since every user has basically opted-in to your list when they registered on your website.

What’s bad about single opt-in?

  • Users may commit typos when keying in their email address and then wonder why they cannot login with their email address.
  • Users who key in spam bot email addresses or other people’s email addresses to perform mischief.
  • Eventually, the number of bad email addresses in your mailing list will grow till you get marked as a spammer when you send out emails to those bad email addresses.

What’s good about double opt-in?

  • User email addresses are verified as belonging to the person who registered and opt-in consent is explicit. This is great for complying with the European Union’s General Data Protection Regulation (GDPR).
  • Reduce bounces since your mailing list will only contain verified email addresses.
  • Save money on sending emails since you have a smaller but verified list instead of a large and useless list.

What’s bad about double opt-in?

  • Users may be confused over the need to click a link to verify their email addresses and ignore the link.
  • Your verification email may be lost or trapped in the spam folder.


As you can see above, there are downsides to both styles. Ultimately, it is up to you which you would rather go through or which you would rather your users go through. But if you have to comply with personal data protection regulations, then you must practice double opt-in as there might be financial penalties involved for failure to adhere to regulations as in the case of the GDPR above.

Get started with MailboxValidator

Improve your email deliverability and sender reputation in email marketing.

Register today and clean your email lists for FREE!

Was this article helpful?

Related Articles