Four Email Deliverability Best Practices

Being a successful email marketer requires creative and technical knowledge. If you don’t have a healthy mix of both, your email marketing program will suffer. One of the most important technical aspects of email marketing is deliverability. Without a healthy sending reputation, your email program might not even exist.

Let’s dive deeper into what it takes to maintain a healthy deliverability score.

Subscriber list

There are ways of obtaining a subscriber list that are acceptable and others that aren’t.

In the United States, the rules of gaining opt in from subscribers are relatively lenient. Anyone who shows interest in your company, whether they buy your product, sign up to receive your newsletter, or fill out a contact form, is generally considered opted in and can receive any email from you.

The rules in other countries, are much stricter and usually require email marketers to utilize a double opt in process. It is important for global marketers to keep up to date with the laws in every country, as they frequently evolve.

If you’re unsure about whether an opt-in tactic qualifies, it’s always better to check and be conservative. A subscriber who doesn’t believe they should be receiving your email will automatically mark it as spam, and hurt your sending reputation.

In addition to subscribers expressing interest in your product, another form of obtaining email addresses is buying and selling lists. Although it is legal, this practice automatically lowers your credibility to a subscriber. If you don’t overtly communicate to the subscriber that their email addresses could be bought or sold and mention the specific names of the companies, they will likely mark your email as spam.

List maintenance

Once you obtain a legitimate list of opted in users, it is important to react quickly to their behavior.

Consistently monitoring engagement metrics, such as opens, clicks, and bounces, helps keep a pulse on the relevancy of your content and lists. If your engagement metrics start to fall below industry standard, perform a list hygiene campaign. Send an email asking your subscribers if they want to continue receiving your emails to confirm who is engaged and eliminate who is unengaged.

In addition to engagement metrics, it is just as important, if not more, to monitor your unengaged subscribers. Having a list full of unknown users, spam traps, and inactive users will permanently hurt your reputation if not taken care of immediately. Unknown users can appear if you have an old list and will return as a hard bounce. Remove hard bounces the first time they bounce.

Sending patterns

If you want ISPs viewing you as a professional email marketer, your sends must be as consistent as possible.

Putting all of your campaigns on an automated schedule helps achieve this. Develop a promotional calendar for and prepare content blocks on a monthly basis. Then, switch out the content of the emails in the automation instead of batching and blasting.

It’s not recommended to send promotions on a daily basis. However, establishing a consistent cadence and sending to engaged subscribers regularly signals to the ISP you’re not a spammer.

Lastly, if you have larger campaigns sent to your whole list, like monthly newsletters, it is imperative that you throttle sends to a slower, consistent hourly rate. This will show the ISP that you’re aware of your list size and are taking conservative precautions. Otherwise, a large surge in emails sent from your IP address will be perceived to the ISP as bulking, which is a common way that spammers operate.

Content Dos and Don’ts

Email content has a large effect on reaching subscribers’ inboxes. What you say and how you say it can either be a red flag or a green light to an ISP.

Promotions are one of the trickiest campaigns for determining acceptable content. You might be inclined to mention that something is a “% off” or “free.” However, those two phrases are some of the most obvious signals to ISPs that you might be a spammer. Even the mention of “cash,” “price” or “discount” can hurt your inbox placement.

What’s more, the same rules apply to subject lines. Choosing language that is less promotional for your subject line, as well as the body of your email, is key to landing in the inbox.

In addition to the content of your email, the HTML skeleton of your template weighs just as heavily to ISPs in deciding whether to accept your email. If the HTML isn’t perfectly coded, the email won’t render correctly. That signals to the ISP or subscriber that you’re not a professional. Every ISP has their own coding preferences, rules and caveats, so keep up with industry trends, and consistently research individual ISPs to stay ahead of the competition.

Language and HTML are just a few of the endless criteria ISPs look for in deciding to accept your email. According to ReturnPath, some examples of additional factors include header, footer, images, text color, timestamp, URLs, text-to-image ratio, language, attachments, and more.


Email marketing is a channel that is always evolving. It also takes time to learn your audience and determine what works best for them. Once you do, your deliverability will fall into place. The best way succeed in email marketing is to keep up with the trends and exercise best deliverability practices.

Jenny Rooth is an Online Marketing Coordinator at cleverbridge.

Learn more about Email Marketing at cleverbridge