Five Best Practices for Email Deliverability

These five best practices will help you improve deliverability for your email marketing
Feb 26, 2020
Brad Gurley

It’s not news to us (nor likely to you) that email marketing is one of the top drivers of customer engagement, yielding the highest potential ROI of all marketing channels. Marketing departments are often building entire budgets around email marketing — but are they optimizing their email efforts to improve deliverability?

According to 250ok, delivery to the inbox for North America was around 88% in 2019, but the DMA reports that some industries saw much lower deliverability. While trends in deliverability and engagement are trending upward as a whole, the industry average doesn’t mean much if your organization’s mail isn’t making the cut.

Nearly all major mailbox providers (MBPs) utilize machine learning to determine how they should filter inbound mail. Their primary goal is to ensure their users are happy, by delivering “wanted” mail to the inbox and keeping everything else out — whether it’s never delivered or filtered to spam. These filters monitor user engagement and sender reputation in real time to determine how mail is routed on their networks.

As a sender, you’ll need to follow some core best practices if you want to be sure your mail reaches the inbox.

List Building and Consent

Organic list growth, along with acquiring clear opt-in, is the cornerstone of good deliverability. Building a list through purchase, email appends, or any other third-party source will damage your sending reputation and chances of reaching the inbox.

It’s not a new concept, but it’s crucial to understand that higher volume doesn’t necessarily mean higher ROI. Sending to purchased or otherwise non-permission lists will drive high hard bounces, complaints, and trap hits — all facets that can seriously hurt your deliverability. Building your email database the right way will help keep engagement high and emails in front of the consumers that matter. If you’re not following best practices in acquiring your subscriber database, you’re not likely to see optimal inbox placement — even if you’re following the other suggestions on our list.

List/Data Hygiene

Even a permission-based list of recipients isn’t guaranteed to never have deliverability issues. Over the life of a subscription, an email address may change or be abandoned, or the subscriber may lose interest or unsubscribe. This is why it’s so important to manage and clean your data consistently — removing hard bounces, complaints, and unsubscribes in a timely fashion.

You may be especially susceptible to list hygiene issues if you offer a one-time promotion, contest, or discount on a product. Consumers may even sign up fake or mistyped addresses, which commonly end up being invalid (hard bounce) or, even worse, a spam trap. Recipients who signed up more than a year ago may no longer have an interest in (or even remember signing up for) your emails. Attempting to re-engage — and eventually removing — unengaged recipients on a regular basis is a great way to maintain strong deliverability.

Consistent Sending Patterns

A consistent sending frequency and cadence is key; this allows recipients to have expectations for your emails. MBPs rely heavily on patterns and consistency when assigning a sending reputation. Sending emails on a repeated pattern (same days each week, roughly the same volume for each type of mailing) helps the providers identify and assign a reputation for your mailstream. Sending a triggered welcome message upon sign-up is a great way to remind users why they subscribed and to set the expectation for tone and frequency. Once you’ve set those expectations, recipients are more likely to also remember when to look for your messages and what type of content and branding they’ll see within.

Setting up a preference center, allowing users to control the amount and type of emails they want to receive from a brand, can be helpful in driving engagement and limiting complaints/unsubscribes. Once you’ve set the expectation (either by welcome message, preference center, or otherwise), stick with it. Reach out to your subscribers if you’ll be experiencing any notable change in sending frequency, branding, or content.


Targeting your most engaged users most frequently is a great way to start generating better inbox placement and engagement metrics. Another is to use the data you have to personalize the messages and make them more relevant to the recipient. Using subscriber information like location, age, gender, purchase history, and browser behavior will help better target your subscriber base and drive their engagement. Optimizing the times email campaigns are sent is another great way to ensure messages aren’t missed and help keep engagement high. The better you are able to identify what your subscribers want and how to provide it to them, the more likely you are to reach and resonate with them.


The rate at which consumers are reading emails on mobile devices continues to rise. Litmus reports that around half of all email opens take place on a mobile device. Extensive testing to ensure mobile optimization (not just compatibility!) should be a no-brainer in 2020. A poor user experience could mean no response, no action or, in other words, no ROI.

Another important element of mobile engagement is the unsubscribe method. Recently, both Gmail and Apple implemented steps to make it easier for recipients to unsubscribe on their mobile apps — with links that appear at the very top of email messages. While data has shown that recipients aren’t likely to unsubscribe just because these links exist, they will be if your message isn’t engaging and relevant right off the bat.

This is by no means a comprehensive list; email deliverability will only continue to become more complex as AI algorithms and Machine Learning become more prevalent and advanced. But following these basic best practices will build a foundation for good deliverability for now and years to come.


About the Author

Brad Gurley

Serving as MessageGears’ Director of Deliverability, Brad spends his days watching mail queues, analyzing customer delivery data, and researching the latest updates to email technology. He’s been in the email marketing space for the better part of two decades and harbors a passion for educating senders on how to more effectively deliver mail to their subscribers. When he’s not busy updating MTA configurations, you might find him preparing a variety of smoked meats or leading a group of friends to the closest karaoke bar.