Best practices: Email deliverability

Ensuring optimal subscriber engagement is one of the key ways to maximize the deliverability of your email program. When you optimize for subscriber engagement, you increase the likelihood that your emails will be successfully delivered to primary email inboxes, i.e., not delivered to junk/spam folders. If you don't optimize for subscriber engagement, your emails are more likely to be blocked by spam filters or reported as spam by subscribers.

Make sure subscribers opt in

Your email program will be more successful when subscribers actively opt in to receive emails from you. When subscribers don't opt in, they’re more likely to report your message as spam.

In a few cases, customer opt in may not be necessary. For example, consider a customer who provides an email address, adds items to their cart, then starts and abandons checkout. This customer is active and engaged on your site, so it's reasonable to assume they would welcome being contacted. Nevertheless, in most cases it’s still a good idea to get permission before contacting customers.

Attentive’s sign-up units make it easy for you to grow your subscriber list. They’re a proven way to convert visitors to email (and SMS!) subscribers. They’re also easy to customize so that subscribers know what kind of content to expect when they opt in to your email program.

Finally, never purchase an email list. Using purchased lists can seriously damage your sender reputation and subscriber engagement.

Send relevant and engaging emails

Send emails that are relevant and engaging.

Relevant emails are those your subscribers want and expect to receive. You can make it clear when subscribers opt in what kinds of emails they’ll receive and how often.

For example: You create a sign-up unit that says subscribers will receive weekly emails. These emails will announce discounts, new products, and product updates. Generally speaking, you shouldn't send emails more than once a week, and you shouldn't use them to make unrelated announcements.

Engaging emails use industry best practices to keep subscribers engaged. These best practices include the following:

• Write clean subject lines
• Use both images and text
• Use hyperlinks sparingly
• Personalize

Write clean subject lines

The subject line is one of the first things subscribers notice about an email. A good subject line tells subscribers what to expect and entices them to open the email. Make it short and punchy.

Good subject lines also avoid the following pitfalls:

• All caps
• Excessive punctuation
• Excessive use of special characters or emojis
• Words or phrases known to trigger spam filters (e.g., “free,” “act now”)
• More than 40-50 characters in length

Use both images and text

Engaging emails contain a balanced mix of images and text. We recommend a ratio of 40% images to 60% text. Subscribers and spam filters associate image-only emails—i.e., emails with text embedded in an image—with spam. Image-only emails are often caught by spam filters before they can be delivered. But even when they’re delivered, subscribers are more likely to report them as spam than emails with both text and images.

Image-only emails also make it difficult for screen readers and other assistive technologies to read the content.

Attentive provides a number of prebuilt layouts with a balanced mix of images and text that you can use as templates. See Email templates and saved rows for more information.

Use hyperlinks carefully and sparingly

Using too many hyperlinks increases the likelihood that your email will be flagged as spam. Be mindful about how many links you include in your email, especially if they link to sites other than your own. We recommend including no more than two or three links. And remember that including too many links also increases the size of your message. Some mailbox providers, like Google, won’t display the entire message if it’s above a certain size, which can cause issues with tracking open rates.

We also recommend that you avoid using third-party link shortening services (e.g., bit.ly). URLs created using these services are more likely to trigger spam filters because they’re often used by spammers. Generally speaking, the domain of the links in your emails should match the domain you’re using to send emails.

Personalize

Attentive makes it easy to personalize emails by letting you add subscriber-specific details. Your emails can include a subscriber's name, the names and images of products they've viewed or added to their cart, and more. When you personalize emails with these details, subscribers are more likely to engage with them by opening them, clicking links, and making purchases. They're also less likely to report them as spam.

Test your content

Consider A/B testing your campaigns to find the subject lines, text, images, links, and offers that drive the most engagement. We recommend testing one major variable at a time. And don't just set it and forget it—continue to re-test and refine throughout the year.

Also consider testing variations of the number and type of calls to action. Studies have found that having more than 10 unique links or offers in emails leads to a decrease in clicks and other engagement metrics, but you may want to test to confirm whether this is true for your brand. For example, a daily deal brand may find that a higher count of offers and links in their emails works for them because that’s what their subscribers and mailbox providers expect.

Send at the right time

Generally speaking, these are the best times to send campaign and marketing emails (in the subscriber’s local time):

• 7:05 AM
• 11:05 AM
• 6:35 PM

Sending at these times can prevent your emails from being buried in subscriber inboxes, which can hurt open and click performance.

Avoid sending on the half hour or at the top of the hour

We don’t recommend sending emails on the half hour or at the top of the hour (e.g., 7:00 AM or 7:30 AM). This is when mailbox providers receive the most mail (especially spam). It’s also when their algorithms are most aggressively blocking and filtering email. If you want to send emails on the half hour or at the top of the hour, we recommend that you instead send those emails 5-7 minutes later.

Avoid sending after business hours

We don't recommend sending emails between 8 PM and 7 AM (local subscriber time).

Find the best days of the week to send

The best day of the week to send emails can differ from industry to industry. For example, retail and sales should follow common pay schedules on the 15th and 30th. Some people are paid weekly or biweekly on Fridays, so sending emails on a Thursday evening prior to a Friday sale can also be a good strategy.

Test your send times

Consider A/B testing to find the dates and times that lead to the best outcomes for your brand.

Make it easy to unsubscribe

It's not a bad thing when someone unsubscribes from your emails. While it's true that you’re communicating with one less potential customer, the quality of your list actually improves. Remember, subscriber engagement is the key to email deliverability. When someone unsubscribes, you lose someone who was unlikely to engage with your emails anyway.

It’s important that your emails include a prominent, one-click unsubscribe button. It not only helps you stay consistent with legal and regulatory requirements but also reduces the likelihood that subscribers will report your email as spam. Attentive also includes unsubscribe information in email headers. Mailbox providers use this information to recommend that users unsubscribe from emails they don’t engage with.

Keep your email subscriber list clean

One of the most important ways that you can improve email deliverability is by regularly cleaning your email subscriber list. Keeping a clean subscriber list can improve your sender reputation, boost engagement rates, and help ensure your messages are delivered to subscriber inboxes. It also decreases the time needed for a “warm-up” period when starting a new email program with Attentive.

The Attentive platform has built-in, automated email hygiene processes that help keep your email subscriber list clean. Any email addresses that are invalid at signup are suppressed based on the below criteria. Your subscriber list is also regularly checked and any additional invalid or ineffective email addresses are suppressed.

The following criteria are used to determine whether an email address is invalid or ineffective:

• domain name typos (e.g., gmai.com, hotmal.com)
• addresses of subscribers who mark email from your brand as spam
• addresses blocked more than three times
• hard bounces (i.e., the email address is invalid or doesn’t exist)

You should also consider creating sunset segments and journeys to identify and re-engage subscribers who haven’t opened or clicked on email messages from you. Creating sunset segments and journeys can help you:

• Renew subscriber interest in your emails
• Remove subscribers from your list if they’re no longer interested
• Reduce your email list size
• Improve your deliverability and engagement rates
• Avoid sending unwanted messages to unengaged subscribers