What are opt-in policies and why do they matter?

In simple terms, an opt-in policy is the rules we set out when someone wishes to subscribe to our email list.

In your email marketing platform (e.g. ConvertKit) there are built-in capabilities to cater for both a ‘single‘ opt-in policy, and a ‘double‘ opt-in policy.

Which you choose to employ*, is down to you.

*I should state here that the decision to elect a single or double opt-in is NOT at an account level in your email marketing system, but instead can be individually selected at an opt-in form level.

What is a ‘single’ opt-in policy?

Whenever someone elects to subscribe to our email list, it’s normally done via an opt-in form that looks something like this;

A subscriber will typically enter their name and email address, click the submit button, and that sends the data to the email marketing platform (sometimes referred to as ’email service provider’).

When the data arrives at the email platform, if there is a single opt-in policy in operation then the subscriber will immediately be added to the list as a ‘confirmed‘ subscriber.

From that point onwards, that subscriber will be sent emails, just like any other subscriber.

What is a ‘double’ opt-in policy?

In exactly the same way the as the ‘single’ opt-in above, a double opt-in policy begins by collecting the subscriber’s name and email address and passes the details back to the email platform.

This time, when the details are received, the email platform marks the subscriber as ‘unconfirmed‘ and is immediately ineligible for any email campaigns.

The confirmation email

All subscribers coming via this route is then sent an email asking them to click a button (or link) to confirm that they own the email address that was submitted and that they’re happy to join the email list.

Only when they click on that button in that confirmation email, are they then marked as a ‘confirmed‘ subscriber and eligible for email marketing campaigns.

What to consider when deciding on which policy to employ

If you employ a SINGLE opt-in policy:

The advantages:

  • It’s quicker for subscribers to sign up (no need to confirm).
  • Subscribers can begin to access your lead magnets more easily.

The disadvantages:

  • Erroneous data entry:

You can potentially add erroneous email addresses to your subscriber list. For example, let’s say I joined your list but made a typo when submitting the form, I could end up on your list as “jonh@email.com” instead of “john@email.com” (not my actual email, of course).

In this scenario, I would be confirmed as a subscriber, but probably get flagged as a non-existent email address (unless the erroneous email existed too).

  • Bots list-bombing you:

As we all know, the web has its fair share of bots that just crawl about looking for mischief! One of those threats is when they come across an opt-in form and they can begin to flood your email list with fake email addresses – this is commonly known as ‘list bombing’.

You don’t want to be using a single opt-in policy if this ever happens, especially if you have automated email sequences set up to run, because your email marketing platform will begin trying to send emails to all those fake email addresses which will only result in bounced emails and your deliverability rate being affected.

  • Masquerading subscribers joining:

This is where someone subscribes to an email list using the email of someone else, and an address they do not own. For example, if I wanted to, I could find your email address and submit it to many lists without you ever knowing.

You would begin to receive emails from the email marketers and believe they are spamming you because you never asked to be on their lists.

If you employ a DOUBLE opt-in policy:

The advantages:

  • It’s only ever bona fide subscribers who get confirmed.
  • You maintain a cleaner email list which helps deliverability.
  • You are protected from bots list-bombing you, and invoking emails.
  • As subscribers need to make the extra step, they’re normally more engaged.
  • You can take advantage of the confirmation email to capture zero-paty data.
  • You’ll have evidence to support any potential data privacy issues (e.g. GDPR).

The disadvantage:

  • More effort required to join

The additional required step (i.e confirmation email and button) can result in some subscribers not following through with their intention to subscribe – they will remain as ‘unconfirmed’ subscribers on your list.

Which opt-in policy do I use in my email marketing?

As you’ve probably guessed by now, I employ a double opt-in policy on all of my landing pages and opt-in forms. Everything about it just sits more comfortably with me.

I like that everyone who joins my list is there because they want to be and have taken affirmative action (i.e. clicking the button in my confirmation emails) to keep my email list clean.

Would I ever employ a single opt-in policy?

Well, yes, I would – but with caveats.

I can see the advantage of having a single opt-in, because of the simpler process for subscribers, especially with the proliferation of auto-populating form fields (i.e. the browser can automatically fill in your email address for you, and therefore reducing typos), so I understand the attraction.

If I did employ a single opt-in policy, I would automatically feed all my subscribers into a cleansing email sequence – where anyone who didn’t open or engage with my emails within the first 7 days of subscribing would be unsubscribed automatically from my list.

I would also remove any emails that bounced as that would be a red flag right away.

That said, I still have no plans to use a single opt-in policy any time soon!


I hope this article has given you enough information to allow you to make an informed choice when it comes to your opt-in policy for your email marketing system.

What opt-in policy will you be using, and why?

John Bellingham
Email marketing strategist for aspirational freelancers.

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