Double Opt-In vs. Single Opt-In: The Best List Building Method for eCommerce Business

Building a high-quality email list is essential for the success of any email marketing strategy, especially for eCommerce businesses. The method you choose to capture subscriber information directly impacts your list’s quality, engagement levels, and overall conversion rates. Two of the most common email list-building methods are single opt-in and double opt-in.

In this article, we’ll compare these two email opt-in methods to help you determine which one is best for your eCommerce business. We’ll break down how each method works, its benefits and drawbacks, and how to optimize your email sign-up process for better deliverability, engagement, and conversion rates. By the end, you’ll have a clearer understanding of which opt-in method will best align with your eCommerce brand and objectives.

Before diving into the specifics, as always, let’s start with the goal.

Ask yourself: What is your ultimate goal when collecting contacts for your email marketing campaigns?

You might be wondering why this is important. The answer is simple: data! Understanding your goal will help you choose the right method. Let’s look at how single opt-in and double opt-in perform when aligned with different objectives.

When it comes to quickly growing your email list, single opt-in tends to yield higher subscription rates. According to research by GetResponse, the average subscription rate for single opt-in is 1.28%, which is significantly higher than the 0.33% for double opt-in. This makes single opt-in an attractive option for businesses looking to expand their email lists rapidly.

However, while single opt-in brings in more subscribers, double opt-in results in much higher engagement. Subscribers who go through the double opt-in process are more likely to interact with your emails. For example, in the arts and entertainment sector, the open rate for double opt-in is 41.95%, compared to just 19.71% for single opt-in. This data clearly shows that although double opt-in may generate fewer subscribers, it results in a more engaged audience who is more likely to take action on your emails.

Which Method Is Best for Your Ecommerce Brand?

Now that you know the data, let’s dive into the details of each email list sign-up method, and I promise you, by the end of this article you’ll be ready to decide!

What is Single Opt-In?

So, what exactly is a single opt-in? From my perspective, it’s the easiest method for collecting email addresses. When a user enters their email into a sign-up form, they are immediately added to your email marketing list, with no additional steps required. As soon as they submit their email, they gain instant access to the content, offers, or incentives you’ve promised—no need to check their inbox for a confirmation email.

Now, let’s take a look at why single opt-in is so popular, and let me show you its advantages.

First and foremost, it’s incredibly quick and easy. One of the main reasons it’s widely used is that it simplifies the process for the user. They simply type in their email, hit submit, and they’re done. This low-friction process means there’s less chance of abandonment during sign-up, leading to more people joining your email list. It’s hassle-free, and from my experience, I can confirm, everyone loves simplicity!

Next, single opt-in offers instant access. Subscribers don’t have to wait for a confirmation email. Whether it’s a download, a special offer, or a product sneak peek, they get immediate access to what they’ve signed up for. This instant gratification not only makes your subscribers feel valued, but it also keeps them engaged from the get-go, enhancing their overall experience with your brand.

Another key advantage is the higher conversion rates it can bring. Since there are no extra steps for users to take, single opt-in eliminates barriers to signing up. This typically results in more subscribers joining your list and, therefore, higher conversion rates for your email pop-ups. The simpler the process, the higher the likelihood of sign-ups.

However, as with anything, there are some downsides to using a single opt-in. The first major drawback is the potential for lower email list quality. While single opt-in boosts sign-ups, it also increases the risk of incorrect, mistyped, or even fake email addresses being added to your list. These invalid emails could harm your email list quality and impact your deliverability (a crucial part ofyour email marketing success), and engagement in the long run.

Another disadvantage to consider is the higher risk of spam complaints. Without the second step of confirming the subscription, some users might forget they signed up, and in turn, could mark your emails as spam. This could negatively affect your deliverability rates and make it harder for your emails to reach subscribers’ inboxes in the future.

Lastly, there’s the issue of lower email marketing engagement. With single opt-in, you’re more likely to end up with a larger but less committed email list. Subscribers who haven’t taken the extra step to confirm their interest might not be as engaged with your emails, leading to fewer opens, clicks, and conversions. Ultimately, this could hurt your conversion rates.

Let’s sum up: single opt-in is a great method for growing your email list quickly and boosting conversion rates, but it comes with its own set of challenges. If you prioritize speed and simplicity, single opt-in might be the way to go. However, if you’re looking for higher-quality subscribers for a long-term game and better engagement, you may want to consider the double opt-in method as an alternative.

That’s being said, let’s dive into the details of double opt-in.

What is Double Opt-In?

Double opt-in method, in contrast to single opt-in, involves an extra step to confirm a subscriber’s intention to join your email list. After entering their email address, the subscriber receives a confirmation email, which contains a link they must click to complete the subscription process. Only after clicking this confirmation link are they added to your email list. This ensures that the subscriber genuinely wants to receive your email marketing campaigns, and helps filter out invalid or unwanted sign-ups.

Now, let’s explore the advantages of double opt-in. First, it leads to higher-quality email lists. Since subscribers must confirm their email address, there’s less chance of fake or invalid addresses getting added to your list. This means you get a more engaged and committed audience, perfectly to communicate with from my experience, which is key for building long-term relationships and driving conversions, as well as grants you a stable deliverability rate.

Another big advantage is improved engagement. Subscribers who complete the double opt-in process are more likely to interact with your emails. They’ve taken an extra step to confirm their interest, which often translates to better open rates, higher click-through rates, and a more active audience. This higher engagement results in better overall performance for your email marketing campaigns.

Additionally, double opt-in significantly boosts deliverability rates. Since subscribers have actively confirmed their subscription, they’re less likely to mark your emails as spam. This helps protect your sender’s reputation and ensures that your emails are more likely to land in the inbox rather than being sent to the spam folder.

However, double opt-in isn’t without its drawbacks. The main disadvantage from my point of view is the higher friction it creates for the user, and, as we know, people are lazy. Unlike single opt-in, where subscribers are added to the list immediately, double opt-in requires users to take an additional step—clicking the confirmation link in the email. This extra action can lead to lower conversion rates in sign-ups, as some users may forget about the email or get frustrated with the extra effort, causing them to abandon the process altogether.

In summary, double opt-in is an excellent choice if you’re looking to improve your email list quality, boost engagement, and ensure better email deliverability, or your goal is long-term relationships. However, it does come with a slightly higher barrier to entry for users, potentially resulting in fewer sign-ups. Balancing the pros and cons of double opt-in depends on your email marketing goals and the level of commitment you want from your subscribers.

For your convenience, I’ve summarized all the provided details into one comparison table:

Key Differences Between Single Opt-In and Double Opt-In

When to Choose Double or Single Opt-In Depending on Your Niche and Goals

Choosing between single opt-in and double opt-in ultimately depends on your niche, business objectives, and email marketing strategy. Both methods come with their own advantages and drawbacks, as we’ve already overviewed, so understanding your goals is essential for selecting the right approach.

When to Choose Single Opt-In

1. High-Volume Email List Building (Ecommerce & Retail) If your goal is rapid list growth, particularly for ecommerce businesses in the vape industry, single opt-in can be a great choice. Since this method allows for a quick sign-up process, it can help you expand your list faster. For instance, if you’re running an email campaign for promotions or product launches, the more subscribers you gather quickly, the better your chances of increasing sales.
   

   Case Study: Overcoming High Market Competition in the Vape Industry

   One of our clients in the vape industry faced significant challenges due to intense competition in the market. To stay ahead, they needed to be agile with campaign planning, flexible in their design approach, and, most importantly, streamline their email opt-in process. The primary challenge was double opt-in: given their goals, the competitive landscape, and the need for quick results, it became clear that a single opt-in approach would be more effective for managing deliverability while driving higher sales.

   Initially, we started by sending campaigns to a list of 50k contacts. Over six months, we were able to increase this number to 150k, showing significant growth. While the open rates did drop slightly due to the increased list size, we managed to maintain solid engagement levels thanks to segmentation and targeted planning. This approach ultimately led to a nearly 20% increase in conversion rates.

   By optimizing deliverability and using smart segmentation, we were able to balance the scale of list growth with effective engagement, ensuring both higher reach and better sales performance. This case highlights the importance of adjusting your email marketing strategy to meet the specific needs of your niche and how flexibility in your opt-in process can lead to impressive results.

   For more deliverability insights I recommend reading our guide on how to improve your business deliverability rate.

2. Low Engagement Expectations (For Lead Gen Campaigns or Newsletters) If your emails are less about conversions and more about awareness, single opt-in can work effectively. For newsletters or less targeted campaigns, you’re likely more focused on volume rather than engagement. In this case, single opt-in allows you to cast a wider net.
   • Example: News sites or bloggers who provide regular content can use a single opt-in to grow their audience rapidly without requiring each person to confirm their subscription.

3. Minimal Barrier for New Subscribers When the goal is easy access for new subscribers, especially when offering free resources or content like eBooks, single opt-in lowers the entry barriers. It enables immediate access to the content, making it attractive for users who want fast, no-strings-attached benefits.
   • Example: SaaS companies offering free trials may prefer single opt-in to reduce friction for signing up, ensuring potential customers don’t abandon the process halfway.

When to Choose Double Opt-In

1. High-Quality Subscriber Engagement (B2B, Professional Services, & Niche Businesses) If your business requires a high-quality email list with an engaged audience, double opt-in is the way to go. By requiring a second step, you ensure that subscribers genuinely want to hear from you, leading to better engagement rates (open rates, clicks, conversions).
   • Example: For B2B businesses, where the goal is to nurture long-term relationships with highly targeted clients, double opt-in will attract individuals who are committed and engaged.

2. Ensuring Compliance with Regulations (GDPR, CAN-SPAM) If you are operating in a market where compliance is critical, such as with GDPR in Europe or CAN-SPAM in the U.S., double opt-in helps you meet the legal requirements for obtaining explicit consent from subscribers. This added layer ensures that your email marketing campaigns stay within legal boundaries and maintain a good sender reputation.
   • Example: If your email marketing targets EU customers, double opt-in ensures you remain compliant with GDPR, safeguarding your brand from potential fines.

3. Reducing Spam Complaints and Improving Deliverability: Double opt-in helps reduce spam complaints because users have explicitly confirmed their interest. As a result, you’re more likely to see your emails land in the inbox, not the spam folder. This is especially critical if you’re sending emails to a list that may include less engaged subscribers or ones who may not recognize your brand immediately.
   • Example: If you’re sending transactional emails or drip campaigns for financial services or any industry where trust is vital, ensuring high-quality engagement is crucial. Double opt-in reduces the chances of spam complaints and boosts email deliverability.

4. Long-Term Email List Health (Subscription-Based Services, Niche Markets) For businesses that rely on long-term customer relationships or niche markets, double opt-in ensures you’re not just growing your list in numbers but also in quality. When the goal is customer retention and personalized engagement, confirming the user’s interest with a second step leads to higher customer loyalty and lower unsubscribe rates in the long run.
   • Example: Subscription-based services like magazines or educational platforms benefit from double opt-in because it helps ensure they’re building a highly engaged list over time.

Case Study: Overcoming Bot and Inactive Subscribers in the Sports Industry

One of our clients in the sports industry was struggling with a significant number of bots and inactive subscribers in their database. The issue stemmed from using single opt-in, which often led to low-quality sign-ups in their niche of app discovery and testing. Initially, the problems were manageable thanks to smart segmentation and sunset flow, but with recent changes in Klaviyo pricing, maintaining such a large, unengaged list became increasingly expensive.

To address this, we made the decision to switch to double opt-in. In addition to this, we optimized sunset flows conditions and manually suppressed the low-quality, old contacts. While this transition led to a decrease in subscription conversions due to the more stringent opt-in process, it allowed the client to gain better control over their marketing costs. Ultimately, this strategy helped them maintain a more profitable business model by reducing unnecessary expenses on poor-quality contacts while improving overall email deliverability and list quality.

By implementing double opt-in, the client could focus on engaging the most interested subscribers, leading to a more sustainable and cost-effective marketing strategy in the long run.

Conclusion: Which Method to Choose Based on Your Niche and Goals?

The choice between single opt-in and double opt-in depends on your industry, email marketing goals, your audience’s needs, and the type of engagement you’re seeking.

Ultimately, understanding your niche, audience, and marketing goals will guide you to the right decision. By aligning your opt-in strategy with your business objectives, you can optimize your email list growth, engagement, and conversion rates effectively.

Not sure what’s best for your business? Let our experts help you. Request a free consultation here.

How to Improve Double Opt-In Confirmation Rates

Personally, I am a fan of double opt-in, so I do want to share with you some tips on how to get subscribers to complete the confirmation step.

A low confirmation rate can hinder the growth of your list and reduce the overall effectiveness of your email marketing strategy.

Here are key strategies to improve your double opt-in confirmation rates and make sure your subscribers follow through.

1. Send a Clear, Compelling Confirmation Email
   The first step in improving your double opt-in confirmation rates is to send a clear and compelling confirmation email. This email should explicitly explain what the user needs to do next and why it’s important. Make sure the Call-to-Action (CTA) is prominent and easy to understand. The purpose of this email is to remind the subscriber that they are one step away from receiving exclusive content, offers, or benefits, so the email must engage and motivate them to confirm their subscription.

2. Reduce Friction
   Minimize the effort required to complete the confirmation process. Keep the CTA simple and direct—phrases like “Confirm Your Subscription” or “Yes, I Want In” work well because they are clear and actionable. People are lazy, remember? So, the easier users can confirm their subscription, the more likely they are to complete the process, leading to higher engagement and better email list quality.

3. Offer Incentives
   Encourage subscribers to confirm their subscription by offering them something of value right away. Providing incentives such as discount codes, free resources, or exclusive access can greatly increase the likelihood of confirmation. For example, offering a 10% discount or free eBook download after confirmation gives users an immediate reward for their action, increasing their motivation to complete the process.

4. Send a Reminder Email
   If the user hasn’t confirmed their subscription after the initial confirmation email, it’s essential to send a follow-up email. Remind them of the benefits they will receive by confirming their subscription and re-emphasize the value they’ll get from your emails. This gentle reminder can help bring them back to the process, leading to a higher conversion rate.

5. Create a Sense of Urgency
   To motivate quick action, incorporate a sense of urgency in your confirmation email. Phrases like “Your access is waiting” or “Confirm now to receive your exclusive offer” create urgency and make subscribers feel like they’ll miss out if they don’t act quickly. A timely response can lead to a higher confirmation rate and faster engagement with your content.

6. Use a Simple Confirmation Page
   Once the user clicks the confirmation link, the confirmation page they land on should be clean, fast, and easy to understand. The page should leave no room for confusion—thank them for confirming and provide a clear next step or redirect them to a valuable resource. A straightforward page improves the overall user experience and encourages completion.

7. Monitor Confirmation Rates
   Finally, to ensure you’re optimizing the process, regularly track your double opt-in confirmation rates. By monitoring the data, you can identify patterns, adjust your messaging, or tweak your process to maximize success. If you notice a significant drop-off, try adjusting the email content, CTA, or incentive offerings to improve engagement.

Improving double opt-in confirmation rates is key to ensuring the quality of your email list and the effectiveness of your email marketing campaigns. By crafting a compelling confirmation email, offering incentives, reducing friction, and monitoring performance, you can significantly boost your confirmation rates and create a more engaged and responsive audience. These strategies not only help grow your list but also enhance overall email deliverability and engagement—critical factors for ecommerce success.

Best Practices for Both Single and Double Opt-In Methods

No matter whether you’re using single opt-in or double opt-in, implementing best practices is essential to ensure the quality of your email list, improve engagement, and drive better conversion rates. Here are some essential strategies for optimizing both opt-in methods:

1. Segmentation
   Effective segmentation is one of the most powerful tools for improving your email marketing campaigns. By dividing your email list based on specific criteria—such as engagement levels, demographics, or customer behavior—you can ensure that your emails are targeted, relevant, and personalized. This not only enhances subscriber engagement but also ensures that you are sending the right content to the right people. Whether you use single opt-in or double opt-in, segmenting your list will help you maintain a higher-quality audience and improve conversion rates.Looking for more segmentation insights?Take a look at our related article.

2. Clean Your List Regularly
   To maintain a high-quality email list, it’s crucial to clean your list regularly. This means removing inactive subscribers who haven’t engaged with your emails for a certain period. Regular list cleaning helps to reduce bounce rates, avoid sending emails to fake or invalid addresses, and keep your deliverability rates high. Whether you’re using single opt-in or double opt-in, consistent list maintenance will help you stay compliant with regulations and ensure that your emails reach real, interested recipients.

3. Clear Messaging
   Communicating the value of subscribing is key to ensuring high-quality sign-ups. Clear messaging on your sign-up page and in your confirmation emails helps subscribers understand what they will gain by joining your list. Whether you’re offering exclusive content, discounts, or valuable information, make sure your CTA and messaging are clear and compelling. This will not only increase conversion rates but also ensure that the subscribers you gain are truly interested in your brand and content.

By following these best practices, you can ensure a cleaner, more engaged, and more effective email list, whether you choose single opt-in or double opt-in. These strategies will help boost engagement, enhance email deliverability, and ultimately drive better sales and conversions.

Which Method is Right for Your Business?

The choice between single opt-in and double opt-in ultimately depends on your niche, email marketing strategy, and business goals. If your priority is rapid list growth with minimal friction, single opt-in may be the best option. It’s great for industries like ecommerce where fast customer acquisition is key.

On the other hand, if your focus is on maintaining a high-quality email list with engaged subscribers and you’re looking to enhance email deliverability, double opt-in is the better choice. This method works particularly well for industries where trust and compliance are critical, like B2B or financial services.

Consider your audience size, industry type, and regulatory requirements when making the decision. By aligning your opt-in method with your goals, you’ll be able to optimize your email list and improve engagement for more successful campaigns.

Personal recommendation

And my personal recommendation, nothing will show you what’s better for your business than A/B testing. This one can be completed manually and will require some time, but be sure – this will guarantee you the result.

Not sure how to start? Request a consultation from IMPRO Email Agency and let’s get this ball rolling!