Opt-in email marketing: The complete guide

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Opt-in email marketing is the foundation of ethical and effective email campaigns. It ensures that your audience willingly subscribes to receive your messages.

Unlike spammy, unsolicited emails that often end up ignored or marked as junk, opt-in marketing builds trust, engagement, and long-term customer relationships.

By obtaining explicit permission, businesses can connect with interested subscribers. This leads to higher open rates, better conversions, and improved sender reputation. Requiring opt-in for your email marketing campaigns ensures compliance with privacy and email opt-in laws that regulate digital communication.

In this complete guide, we’ll break down everything you need to know, from the types of opt-ins and email opt-in wording examples to legal considerations and best practices that drive engagement.

What is opt-in for email marketing?

As the name suggests, opt-in email marketing is where the customer opts in to receive emails from a brand. Instead of sending unsolicited messages, it ensures brands send messages only to interested recipients.

Opt-in email marketing can help your business build trust, increase engagement, and improve email deliverability. 

This email marketing approach also helps to reduce spam complaints, and strengthens brand credibility, all while aligning with ethical marketing practices and email opt-in rules.

There are two main types of opt-ins you need to know:

• Single opt-in: This happens when a user enters their email and is immediately added to the mailing list. It’s a fast and simple method, but it may lead to spam signups or incorrect email entries.
• Double opt-in: After signing up, the user receives a confirmation email and must verify their subscription. This extra step ensures a more engaged and high-quality list, reducing spam and fake signups.

When is opt-in necessary for email marketing?

From a legal standpoint, regulations like GDPR (General Data Protection Regulation) and the CAN-SPAM Act require businesses to obtain email consent before sending marketing emails. 

GDPR applies to businesses targeting European Union customers. It requires clear, explicit email consent before sending marketing emails. In the US, the CAN-SPAM Act also mandates that marketers must provide an easy opt-out option for recipients. 

Adhering to these regulations ensures compliance. It also supports ethical and effective email marketing. Watch the video below for a step-by-step tutorial on GDPR compliance for email marketing:

Beyond compliance, opt-in is also necessary in the following situations:

• Growing an email list: Subscribers must willingly sign up through forms, popups, or checkboxes
• Sending promotional campaigns: Your brand should only email users who have opted in to receive offers, newsletters, or updates
• Avoiding spam filters: ISPs and email platforms prioritize senders with verified, engaged subscribers

You don’t want to risk fines, poor deliverability, or losing customer trust by sending emails without proper consent. Using opt-in email marketing helps you respect user preferences and also ensures you’re communicating with the right audience.

Understanding implied and explicit email opt-in

When building an email list, marketers must understand opt-in consent and the difference between implied and explicit opt-in methods. While both involve user permission, they differ in how consent is obtained and confirmed.

So, what is opt-in consent? This refers to users voluntarily agreeing to receive emails from your business. 

Have you seen a checkbox stating “I agree to receive marketing communications” or “By signing up, you agree to receive emails” when signing up for a service? These are some of the wordings businesses use to obtain consent.

Another method is sending a consent email, requiring users to confirm their interest before being added to an email list. 

Let’s explore explicit and implied opt-in methods to understand how they impact email marketing campaigns and engagement:

Implied opt-in

Implied opt-in occurs when a business has an existing relationship with a customer who hasn’t directly subscribed to marketing emails. 

While implied opt-in allows businesses to send transactional or service-related emails, it doesn’t guarantee permission for promotional content. 

Implied opt-in happens when:

• A customer provides their email when making a purchase
• A user signs up for a free trial or downloads a resource without explicitly agreeing to marketing emails

Since GDPR requires explicit consent for marketing emails, you can’t rely on implied opt-in.

Explicit opt-in

Explicit opt-in is the premium standard in permission email marketing. Explicit opt-in, or express consent, means the user actively consents to receive marketing emails. 

It ensures GDPR compliance for email marketing and the CAN-SPAM Act. It also results in higher engagement and lower spam complaints.

Explicit opt-in happens when:

• A subscriber fills out a signup form and checks a box to receive emails
• The subscriber then confirms their subscription through a double opt-in process

For ethical and effective email marketing, businesses should prioritize explicit opt-in over implied opt-in to build a high-quality, engaged email list.

Acceptable forms of email opt-in

To build high-quality opt-in email lists, you must use acceptable forms and ethical methods to gain subscriber consent. This is in addition to understanding email opt-in meaning. 

Using these email opt-in acceptable forms ensures compliance while growing your email list from scratch. 

Here are some acceptable ways to obtain email opt-ins:

• Signup forms: A common method where visitors enter their email addresses on a website, landing page, or blog to receive updates or promotions
• Checkboxes on checkout pages: Adding an unchecked box during purchases allows customers to opt in without feeling forced
• Popups and slide-ins: These capture visitor interest by offering valuable content, discounts, or exclusive deals in exchange for an email subscription
• Lead magnets: Free resources like ebooks, templates, or webinars encourage users to opt-in while providing value
• Double opt-in confirmation: Sending a verification email ensures the person genuinely wants to subscribe, reducing spam signups

Unacceptable forms of email opt-in

Not all email collection methods count as valid consent. To maintain transparency, avoid unethical or non-compliant practices when growing your email list. Always adhere to opt-in rules for email. 

Using improper methods can lead to spam complaints, low engagement, and legal penalties under GDPR and the CAN-SPAM Act. 

Some unacceptable ways to obtain email opt-ins are:

• Pre-checked boxes: Automatically selecting an opt-in checkbox assumes consent rather than actively obtaining it. Visitors must manually check the box to subscribe.
• Scraped or purchased email lists: Collecting emails from websites or buying lists violates privacy laws. This leads to unengaged and spam-prone contacts.
• Forced opt-in: Requiring users to subscribe to marketing emails to access a product or service without an alternative isn’t true consent. This may violate GDPR and email marketing regulations.
• Adding customers without permission: Just because a customer made a purchase doesn’t mean they agreed to receive marketing emails. A separate opt-in is required for consent.
• Burying consent in terms and conditions: Hiding email opt-in agreements in fine print doesn’t provide clear, informed consent. This could be a violation of email marketing rules.

Common scenarios requiring opt-in

Knowing when to require opt-in consent can maximize conversions and help you create the best signup form for high conversions. 

Here are seven common scenarios that require your customers to opt in for email marketing:

• Newsletters and content updates: Users must explicitly opt in to receive newsletters, blog updates, or industry insights
• Promotional emails: Customers must provide clear email opt-in consent to receive discounts, product launches, or special offers
• Abandoned cart emails: Customers must opt in at checkout or elsewhere to receive reminders about abandoned items in carts
• Event invitations and webinars: Attendees must opt in to receive follow-up emails for webinars, in-person events, or virtual workshops
• Customer feedback and surveys: Only customers who have opted in should receive review requests or survey participation emails
• Loyalty and rewards programs: Users must actively sign up and agree to receive loyalty perks and rewards program updates
• Re-engagement campaigns: To reconnect with inactive subscribers, you must have prior opt-in consent before sending win-back emails

Opt-in email marketing best practices

Implementing opt-in email marketing effectively can help your brand build an engaged, high-quality email list. To maximize success, follow these email marketing best practices that prioritize user experience and compliance:

• Offer value-driven signups: Providing a compelling reason to sign up increases conversions. Encourage users to opt in by providing incentives like exclusive discounts, free resources, or early access to new products. 
• Use clear and transparent consent: Ensure subscribers understand what they’re signing up for. Avoid pre-checked boxes and hidden terms to maintain trust and compliance.
• Implement segmentation from the start: Organize your opt-in email list based on interests, demographics, or purchase history. This strategy improves targeting and engagement.
• Leverage personalization: Personalized emails have higher open and click-through rates. Address subscribers by name and tailor content based on their behavior and preferences.
• Use a double opt-in process: Sending a confirmation email after signup helps verify interest and keeps your list free from spam or fake signups. Reviewing double opt-in email examples allows you to craft a seamless verification process. 
• Make it easy to opt out: Providing a simple unsubscribe option builds credibility. It also ensures compliance with GDPR and CAN-SPAM regulations.
• Optimize for mobile users: Many subscribers sign up via mobile devices. This is why you must ensure forms and emails are mobile-friendly for a seamless experience.

A well-structured opt-in strategy improves both engagement and trust with your audience. Building a high-quality email list doesn’t have to be complicated. With the right tools, you can simplify the process and drive better results. 

For example, Omnisend is an email marketing automation tool that comes with advanced email automation features, segmentation, and personalization. It helps brands implement opt-in email marketing effectively while also increasing value-driven signups. Experts trust it, and rookies love it.

How to create high-converting opt-in forms

What catches your eye influences your decisions. Your opt-in form is no different. A well-designed opt-in form is important for creating a high-quality email list and elevating conversions.

Businesses must focus on strategic placement, compelling copy, and continuous optimization. Here’s how:

1. Place forms strategically 

Position opt-in forms where users are most likely to engage, such as:

• Website headers or footers for easy access
• Exit-intent popups to capture visitors before they leave
• Blog posts and landing pages where users seek relevant content

For example, Hypebae places its newsletter signup opt-in form on a popup on its landing page. This opt-in email example ensures that visitors are immediately presented with the opportunity to subscribe: 

2. Keep the form simple

Let’s be honest, nobody likes filling out too many fields on a form. Customers find it easier to sign up with just one field rather than having multiple to fill.

That’s why requesting too much information discourages potential signups. A concise form with just a name and email field will help minimize friction and increase signup rates.

3. Write a compelling call to action 

Avoid generic calls to action like “Subscribe” or “Sign up.” Instead, use action-driven copy that highlights value, such as “Get exclusive deals in your inbox!” or “Claim your free guide now!”

Glossier uses an offer-based opt-in form example with the CTA “Claim 15% off” in its opt-in email marketing form, as shown below:

4. Use eye-catching design

A visually appealing design can make all the difference in capturing attention and driving signups. Using bold colors, compelling images, and clear CTAs ensures your opt-in emails and forms stand out.

A clean layout with engaging visuals and easy-to-read text refines the user experience. This makes it more likely for recipients to subscribe. Prioritizing design drives conversions and strengthens your brand’s credibility and appeal. 

5. Build trust with social proof

Adding testimonials, reviews, or subscriber counts (e.g., “Join 50,000+ marketers”) adds credibility and encourages signups. Showing recognizable brand logos can also reinforce trust. 

The image below shows how Trello incorporates social proof by writing “community of millions” on the homepage to build credibility. It also showcases top companies that trust the brand:

6. Leverage A/B testing

A/B testing can transform your opt-in emails. This strategy helps refine subject lines, content, images, and CTAs to maximize conversions. By testing different variations, you can identify what resonates best with your audience and improve signup rates.

With Omnisend’s powerful A/B testing tools, you can experiment with multiple elements to craft high-performing opt-in emails.

Omnisend uses data-driven strategies to deliver high engagement, from optimizing CTAs to writing the perfect subject lines for increased open rates, ensuring success in growing your email list. 

How to handle opt-out requests and maintain compliance

Making it easy for subscribers to opt out is a must to maintain compliance and a positive brand reputation. Including an email opt-in disclaimer in your opt-in forms or an email disclaimer in your campaigns reinforces transparency. They help users understand how their data is used.

Here’s how to handle opt-outs effectively while maintaining compliance:

• Provide a clear unsubscribe link: Every email should include a visible unsubscribe option that requires only one or two clicks
• Honor opt-out requests immediately: Ensure removals happen in real time or within the legal timeframe, which is 10 days under the CAN-SPAM Act
• Avoid guilt-tripping users: Instead of making subscribers feel bad for leaving, offer a simple and respectful opt-out experience
• Offer options for email preferences: A preference center allows them to adjust frequency instead of unsubscribing completely
• Confirm the opt-out but don’t send follow-ups: A confirmation page is helpful, but sending a final email after someone unsubscribes may feel intrusive

Conclusion

Opt-in email marketing is an ethical use of email communication. That said, ethical email marketing isn’t just about compliance, it’s about creating meaningful connections with an engaged audience.

By ensuring subscribers actively consent to receive emails, your brand can build trust, improve engagement, and stay compliant with laws. 

Plus, best practices, such as clear opt-in forms, segmentation, and transparent unsubscribe options, can help your brand maintain a high-quality email list and avoid spam complaints. 

We recognize that managing opt-ins manually can be overwhelming. Omnisend streamlines the process with automated signup forms, segmentation, and compliance tools. 

From building your list to optimizing engagement, Omnisend helps you follow opt-in best practices while driving better email marketing results.