Single Opt-in And Double Opt-in–What Should You Use?

Recently, the email marketing company Mailchimp announced that the default setting of their signup forms was going to be single opt-in. A lot of people who use email marketing were up in arms about this. Why and what should you use?

In most email list providers, double opt-in is the default. It works like this: when a subscriber enters their email address in the signup form, they get an email asking them to confirm. There is a link in that email that they have to click in order to confirm that they want to be on the list. In single opt-in this does not happen. The process might take you to a page that says thank you, but at that moment, you are already on the list.

As you will understand from the above examples, it is much easier to get a lot more addresses when using single opt-in. Less hassle, less chance of an email going unopened, forgotten or undelivered. So why use double opt-in?

Before I go any further, I am going to tell you that I use both, so I am not advocating one over the other, just that there are situations where you want to use double opt-in and situations where single opt-in will do.

According to its advocates, double opt in reduces the chance of someone accidentally or maliciously ending up on an email list. It may be hard to understand the sort of sick people who enter other people’s email addresses on email lists just because they can, because they have time and obviously nothing better to do. It is also amazing what sort of robotic entering processes exist for entering email fake addresses in all kinds of places where emails can be entered.

It really boggles the mind why people would do things like this, but the fact is that it happens.

I have experienced this. I have an app that allows me to run competitions where you give away a prize and people can increase their chance of winning by getting other people to enter in the competition. There are obviously apps that generate fake email addresses on free services like hotmail and gmail and automatically enter these into the competition so that the original entrant (the owner of the app) can have more chance of winning the prize. I am sure these apps are sold at forums that shall not be mentioned, but as owner of the competition, you can spot it easily when you get thousands of entries within a short time period that all point back to the same address and that all use the same syntax.

So, yes, robotic entries happen. It is a risk of single opt-in forms.

If you are with an email provider that charges you per email address, as most of them do, this can potentially inflate your costs. Because all these bogus email addresses don’t need to be verified and because they are normally valid, meaning that if you send an email to them they won’t bounce, if you send an email to your list and include addresses like that, your open rate will plummet.

The potential for misuse of a single opt-in system is huge.

On the flipside of the coin, I don’t know how many email lists I have tried to subscribe to where the confirmation email never arrived and I therefore could not get material I wanted. Also, filling out forms like entering captchas on a tiny mobile screen is a pain, so people would just prefer to do the one click subscribe.

I use a single opt-in form for internal signups and confirmations*, for example in the process where people want to change their email address or put themselves on the ARC list. It seems silly to ask these people to reconfirm their intention, because they’re already on my list and I do not want to risk losing any of them because they can’t jump through the hoops.

So in short, yes, I think you should use double opt-in as default, but also I think that it should be the default option on your mailing list subscribe form. A lot of people won’t have the technical gumption to find out how to change it or won’t even know that they should. This move by Mailchimp seems to encourage artificial inflation of people’s lists and cannot be seen as anything other than a money grab.


* I use Mailerlite which allows the option to enter a tick box on the single opt-in form. Since bots can’t tick boxes, the chance that you’ll get a flood of junk subscribers is vastly reduced.

Here is the box:

Screenshot 2017-11-17 16.49.31

Here is how to turn it on:

Screenshot 2017-11-17 16.50.06

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