Best Practices to Improve Email Deliverability

What is email deliverability?

Email deliverability is simply the ability to get your emails successfully delivered to your recipient's inbox without being filtered out as spam by email providers. 

Although the end goal and concept of deliverability are simple, there are several factors on which it depends, including:

  • Sender reputation – How have your previous emails performed and has your domain or IP behaved dubiously in the past?
  • Email content – Does your email campaign look like spam?
  • Technical aspects – Are your emails properly signed with the right domain and IP? Has the content been altered in any way?

If you’re still a little unsure of how this all adds up or what you can do to improve deliverability, don’t worry.

We put together a list of effective deliverability best practices for you to follow so you don’t have to worry about getting stuck in spam anymore!


  • Use a recognizable sender name
  • Avoid spammy content
  • Everything about Domain Reputation
  • Write compelling (but concise) subject lines.
  • User's content
  • Check if you're on the blacklist.
  • Tone down the font size and color
  • Correct grammar and spelling


1. Use a recognizable sender name


It’s a good practice to always strive to send emails from an email address that contains preferably your personal name with your brand name so that the recipients recognize you.

Why? Simply because in the sea of emails they receive every day, they have to choose which ones to open. And people prefer to open those which include a personal name in the ‘from’ box, rather than an impersonal, generic one.

2. Avoid Spammy Content

Whenever an email is received by an email provider, the content is scanned to check for spam content.

This filter is looking for specific types of content that typically indicate spam, such as:

  • Writing in all caps
  • Using too much punctuation (don’t write 10 exclamation points in a row!!!!!!)
  • Using red font
  • Overuse of spam words (free, cheap, pre-approved, $$$, 100% free, urgent, don’t wait! etc.)
  • HTML errors

If you avoid making the mistakes above, you should be able to pass through this step pretty easily. However, there are a few other terms that we would like you to get familiar with. One of the biggest factors for avoiding spam filter is by painting a decent domain reputation.

What is Domain Reputation?

Domain reputation is a term used to describe domain respectability. This affects whether or not emails from a website arrive in a person’s inbox. Sites without a strong link domain reputation may find that clients aren’t receiving emails from the site because they are going to spam.

Although the reputation of the IP where your emails are being sent from still plays a role, it is no longer the sole factor. In 2009, domain reputation began to affect whether an email was sent to the spam or not. Nowadays, you can have an IP address that has a positive reputation, but your emails can still go to spam due to the domain’s reputation.

How does Domain Reputation Affect Links and Emails?

Unfortunately for many legitimate businesses – many of which are just trying to promote themselves or keep customers in the loop – they are being blacklisted. Their emails are flagged as spam and this hurts their business tremendously, even though they are not spammers.

A blacklisted domain gets added to a list of sites that are deemed as unsafe or a waste of inbox space. Basically, this discredits the site and a person’s business as well. There is not one universal blacklist that is recognized by every email service provider. In fact, each blacklist is slightly different. However, there are some popular go-to lists, which hold weight when it comes to determining whether or not your emails are flagged as spam. Once your domain is added to one or more blacklists, your emails will not reach the majority of your mailing list.

Email is not the only area that may be affected when your site makes a blacklist. Facebook might prevent you from posting links. This means you will lose even more means of promotion as a result. At this point, it will be very difficult to keep in touch with your clients.

Sometimes, if your site is really bad, Google might blacklist the entire website. Being added to Google’s blacklist is probably one of the worst fates a site can have – If it isn’t the worst. Basically, this will doom any website as visitors who click through will see a red warning page that asks if they are willing to risk accessing your site. Since most individuals aren’t going to agree due to the risks, your site will more than likely lose most of its traffic.


What Makes Your Domain Reputable?

The first step you need to take is to scan your site for malware or viruses. Oftentimes, this is what’s behind getting blacklisted. You might have a problem with the operating system, so make sure you repair any issues. Always perform updates as needed.

No matter to what extent your site is blacklisted, you must act quickly. The longer you take, the more customers you are going to lose. Seeing your site associated with warnings or spam just once will damage the trust a customer has in your brand.

3. Write compelling (but concise) subject lines.

A good subject line should contain between 30 and 50 characters (including spaces). Email accounts and mobile devices often cut off any subject lines that go beyond this length. Your email subject line should also create a sense of urgency while giving readers some indication of what to expect once they open the email.

Things you should avoid including while writing a subject:

  • Spammy keywords (urgent, buy now, win, free)
  • All uppercase letters
  • Typos
  • Overuse of emojis
  • Deceptive subject lines that don’t match the email content (these lead to unhappy subscribers who unsubscribe and grow to resent you as a brand)

Remember: the goal of your subject line is to get the people who care about the content within your email to open it, not to get opens at any cost.

4. User's Consent

Opt-in (consent) is the action taken by someone giving express permission to receive email correspondence from someone. The best practice is being very clear what people are opting in to; in exchange for providing their email, what they are agreeing to receive. Best practice also includes clear language that they will have the ability to easily opt-out at any time and how to do so. This is why using bulk mailing from email programs like Outlook or Gmail to people is not a best practice; there is no easy way for people to opt-out of emails sent that way, nor is there generally any record kept of opt-in.


5. Check if you are a blacklisted sender

If your IP address has a bad reputation in the virtual world, your targeted emails are more likely to land in the spam folder. The reputation of your IP address affects your email deliverability rates directly.

There are certain tools, like Multirbl.Valli or MxToolbox, that lets you check if you are a blacklisted sender.

All it takes is to enter the IP address or domain name in the box, and click ‘check’.



6. Tone down the fonts and colors

People seem to pay a lot of attention to the fonts and colors used in the copy. In the previously mentioned Radicati Group study, over 60% of the people surveyed found it unacceptable if the email marketers used irregular fonts, different font sizes, and font colors. And over 70% of people declared that they prefer one-size fonts.

Here’s an example, taken from HubSpot that shows what NOT to do:


Irregular font colors and sizes also alert spam filters, and the same goes for invisible text (white font on the white background for example). 


7. Correct spelling and grammar

Spell-checking and proofreading are essential components of every good email marketing campaign. Incorrect spelling and faulty grammar will damage your credibility with your clients and make you seem unprofessional.

The Radicati Group study shows that 80% of the people surveyed find grammar and spelling errors a capital emailing offence. It makes you seem unreliable and untrustworthy.

These errors are also major spam triggers. So do take the time to edit and proofread.


Wrapping up

Hopefully, you have a better understanding of how your various factors affect your ability to reach your contacts’ inboxes and what you can do to maintain good email deliverability.

Remember the key takeaways:

  • Maximize meaningful engagement with your emails.
  • Only send messages to contacts who want to receive them.
  • Make sure your technical specifications are set up properly with your DNS provider. 

Unfortunately, there is no magic formula that guarantees your emails won’t land in spam. ISPs, ESPs and anti-spam laws are brutal, and there is no definite guide to help you deal with the deliverability issues.

By paying attention to technical issues, taking good care to avoid all spam triggers in the subject lines and email bodies, and by following up appropriately and in a timely manner, you are more likely to preserve your credibility, sender reputation and protect your IP address and domain from ever getting blacklisted.

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