Single vs. Double Opt-in Subscriber Lists

Best Practices in Email Marketing 2019

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When you’re in the beginning stages of creating an email list, you’ll need to decide between single opt-in vs double opt-in.

What’s the difference?

With single opt-in, you add subscribers to your mailing list as soon as he or she subscribes. There’s no further action the subscriber needs to take before receiving your emails.

With double opt-in, subscribers need to do two things before you add them to your mailing list:

  • Provide their email addresses and indicate they want to subscribe;
  • Confirm their subscriptions by clicking the appropriate link in a confirmation email they receive.

What are the upsides and downsides to using single opt-in?


  • Because users have to sign up for your list and confirm their signup, you know that they really want to be on your list. These users tend to have higher levels of engagement with your emails.
  • You prevent spam addresses (fake addresses, addresses entered by a bot, etc.) from being added to your list. Not only does this mean you’ll see lower rates of things like hard bounces, you’ll keep your lists cleaner, making later maintenance (such as list cleaning) easier.


  • You might lose out on customers who don’t confirm their email addresses, even though they did sign up for your emails and want to receive them. Maybe they forgot to confirm, or the confirmation email got caught in their spam filter.
  • You might seem spam-like, especially if the user receives a lot of emails from you soon after signing up. For example, someone might not be thrilled if you send a confirmation email, a welcome email, and your weekly email during the week after they’ve subscribed.

How to Switch Between Single and Double Opt-In When Using Sendloop

Sendloop makes it easy to implement either single or double opt-in lists. This option is managed on a per-list basis, so you can choose whichever makes the most sense for a given list.

To begin, navigate to your Subscribers page, where you will see all of the mailing lists associated with your Sendloop account.

Select the list you want to manage, and click its name. You’ll be directed to the list’s Overview page, where you can then click on Settings.

On the settings page, you can change the list’s Subscription mode.

You can choose between Subscribe immediately and Subscribe after double opt-in confirmation.

When done, click Save to persist your changes.