Email Deliverability: Why Does it Matter?

At Klaviyo, we’ve helped over 50,000 companies grow their online presence and reach their customers through owned marketing channels. Klaviyo users span the globe, selling anything from watches, to water skis, to waffle irons. Despite the variety in location, products, and customer bases, the common thread among the most successful Klaviyo businesses is achieving and maintaining strong deliverability.

In the world of eCommerce and email marketing, the idea of “deliverability” isn’t always front of mind for email senders. As a business owner, your primary focus is on conversions, revenue, and margin; you can’t cash in your open rate. Just like you have to crawl before you can walk, your recipients have to see your emails in their inbox before they can open, click, and convert — that’s where deliverability comes in. Without any notion of deliverability or email quality, our email inboxes would be overwhelmed with messages from spammers and phishers.

Since the inception of email as a communication medium, and especially since its rise as a marketing channel, inbox providers have continually refined the way they assess messages — and especially their senders — to make sure their users’ inboxes consist of messages they want to see. In addition to messages that end up in your spam folder, there are many more that simply “bounce” — meaning the inbox provider doesn’t allow it into your inbox to begin with. In order to make it into the inbox, senders first have to accrue reputation with inbox providers — this reputation correlates with a sender’s deliverability.

Imagine you’re a business owner: you’ve just signed up for an Email Service Provider (hopefully Klaviyo), your eCommerce platform is integrated, and your list of customer emails is uploaded; you’re ready to start sending to your customers and growing your business — and unfortunately, you’ve yet to stumble on Klaviyo’s guide to your first email send.

You’re creating your first marketing campaign: selecting a list with all of your customers [we’ll come back to this later], picking just the right content, and agonizing over the details: is this button in the right place? Will this picture be pushed below the fold? Are all the product links working correctly? Finally, everything in the preview email looks right, you schedule your campaign, and you can take a breath.

The next day (ok, fine, a few hours later) you check your campaign and your jaw drops. Your bounce rate is very low (sub-0.5%), so you know your messages got to your customers’ inboxes — but just 3% of your customers opened your email, a handful clicked through to your site, and a precious few ended up placing an order. What could have happened? Is email marketing just not right for you? Should you turn to alternative marketing strategies like Facebook or AdWords?

What you’ve just experienced isn’t necessarily a freak occurrence, a sudden drop of interest from your customers, or a reflection of your business’s fit in the email marketing space — more than likely, you’ve encountered some of the pitfalls of email deliverability. Deliverability is defined as the status of an email relative to the inbox — if an email winds up in the spam folder, or doesn’t reach the inbox altogether, that can generally be chalked up to poor deliverability.

When customers on an ESP like Klaviyo incur poor deliverability, it’s not out of a lack of care or caution. Having worked in Product at Klaviyo specifically in the Deliverability space, I’ve seen our customers endure the friction of running into deliverability issues without ever knowing it was something they should be concerned with — and ultimately, that was a shortcoming of the platform. We’ve since added features to improve the sending experience on Klaviyo — including (but not limited to):

• Email volume warnings for customers who are still warming their sending infrastructure
• Warnings to alert users when they incur low open rates
• A self-service tool to help customers get onto their own dedicated sending domain quickly and easily
• An in-app warning about our account verification process prior to a customer scheduling their first campaign
• An Intro to Email Deliverability guide in our Help Center

We are continually seeking to further improve and automate the process of achieving strong deliverability for our customers — with our experience, we’ve also put together some additional tips below on how to make sure you’re getting off on the right foot when you sign up for an ESP.

Warm your Sending Infrastructure

If you’re just starting out with sending marketing emails, it’s crucial that you warm your sending infrastructure — regardless of whether you’re using dedicated or shared. “Warming” entails sending emails to only your highly-engaged customers as a way of training inbox providers to recognize you as a “good” sender and, over time, help you reliably get strong inbox placement for your messages.

For more information, check out Klaviyo’s guide to warming your sending infrastructure — otherwise, read on for more information on how exactly to target these engaged recipients.

Send to Engaged Recipients

Sending to engaged recipients — particularly early on in your email sending journey — is critical to improving and maximizing your deliverability. Within Klaviyo, the segment builder tool empowers you to create segments that target only those customers who regularly engage with your content. Here is an example of a highly-engaged segment that can help ensure you are sending only to your most engaged customers:

Send Great Content

The content of your emails also has an impact on your sender reputation. Put yourself in your customers’ shoes when developing the content of your emails — do you want to be receiving emails with dozens of emojis, irrelevant content, or links to mysterious or third-party domains? A few high-level tips to keep in mind:

• Don’t send image-only emails — these often trigger spam filters
• Don’t include numerous links to external domains (i.e. domains that are not your website)
• Don’t use third-party link shorteners like bit.ly

For more information specifically around email design — you guessed it, Klaviyo’s got a guide for that.

Exclude Unengaged Recipients

If you regularly send campaigns that incur a low open rate, you may be sending to too many unengaged recipients. As we’ve noted, the more engaged your recipients are with your content, the more likely your messages are to land in your customers’ inboxes. Conversely, the more you send to recipients who do not open emails from you, the more likely it is for your sender reputation to be degraded — and yes, this often means reducing the number of recipients in your campaigns.

After you’ve warmed your infrastructure, and are regularly sending to engaged recipients, you can also create a segment of unengaged contacts to exclude from all of your campaign sends — for instance, for more general emails like your newsletter:

Another way to increase sender engagement is by monitoring your sending cadence — regularly sending multiple campaigns to the same recipients in a given week is an easy way to drive down engagement due to sheer volume of communication. In many cases with email marketing, less is more — and Klaviyo’s Smart Sending feature for campaigns can help make sure you aren’t sending to your customers too frequently.

Clean your List

One aspect of deliverability that we didn’t touch on in our example above was instances of incurring a high bounce rate — a bounce rate above the ~0.8–1.0% range generally indicates that you’re emailing contacts that are unengaged or inactive. Engaging in regular list cleaning can help drive down your bounce rate, while improving your campaigns’ open and click rates.

At the end of the day, when after you’ve warmed your sending infrastructure, eliminated inactive recipients, fully cleaned your email list, and established your sending cadence, you may notice that you’re emailing fewer customers than you were at the outset. Don’t fret! The more your customers engage with your emails, the more likely you are to have strong long-term email deliverability.

If you’re concerned about reducing your customer count by removing inactive and/or unengaged contacts from your mailing list, you can also explore ways to increase the top of the funnel for your business — a great way to do so is by implementing a signup form on your website, and experiment with driving non-email marketing traffic to pages where they can sign up and learn more about your brand.

Once you’ve established a strong sender reputation and have maximized your email deliverability, it becomes that much easier to reach out to new prospects and customers with your email marketing efforts and keep them engaged. While it isn’t the first thing most people think about when considering their email marketing efforts, deliverability is the backbone of any successful email marketing program.