How to Improve Cold Email Deliverability

Improving cold email deliverability should be of interest to anyone sending out mass emails for work. Our team of email deliverability experts has some tips to improve your email domain for you to check out.
The world of digital sales is growing at an exponential rate, and email is one of the most effective channels for cold outreach. There are numerous benefits of using cold emails to generate leads.

But only if you have a good cold email deliverability.

If your cold email deliverability is not where you want it to be, don’t worry!

There are many simple ways to improve it that you may not have even realized were possible.

With the advice in this article, you can learn everything you need to know about improving your company’s email delivery, warming up a new domain, and avoiding any pitfalls along the way.

What is Cold Email Deliverability?

Cold email deliverability is the percentage of emails received and read after being sent to a group of contacts.

It differs from open rates, which is the percentage of people who opened and read the emails.
Instead, it also involves other factors like click-through rates, spam reports, and spam filters.

Additionally, cold email deliverability is determined by a number of factors, including the content of your emails, whether the recipients are expecting them, and whether they are delivered to the correct inboxes.

For example, if you send an email to one person and they never see it and never receive it, then your cold email deliverability rate is 0%.

On the other hand, if you send an email to someone and they get it right away, then your cold email deliverability rate is 100%.

What are the Metrics for Estimating Cold Email Deliverability?

Since most ESPs keep their email data private, it is difficult to pinpoint an exact number for the perfect cold email deliverability rate.

However, we may create a reasonable estimate by considering deliverability indicators.
These are the key metrics you should pay attention to:

  • The ratio of emails that land in the principal inbox to those that land in the spam bin.
  • The proportion of emails that are delivered.
  • Email bounce rates (both hard & soft bounces.)

An overall deliverability percentage of 95% is advised for cold emailing to be successful. You will start experiencing issues if you get below the number above.

The bounce rate is one crucial measure that needs to be closely monitored. The bounce rate of a targeted cold emailing campaign should be low, especially if your email list has already undergone pre-verification.

A bounce rate of 2% to 3% or less is ideal.

You must spend more time validating email addresses if your bounce rate is higher than that.

What Affects Cold Email Deliverability?

When you are trying to improve cold email deliverability, it is important to remember that multiple factors can affect your emails.

These factors can include the length of your emails, the frequency of your emails, and the content of your emails.

If you want your emails to be received, you need to make sure that your emails are as effective as possible.

  • Length - When trying to improve cold email deliverability, you first need to look at the length of your emails. In general, shorter emails are better for cold emails than longer ones. While no specific length guarantees your email is received, shorter emails are generally better than longer ones.

  • Frequency - If you send too many emails simultaneously, your recipients may mark them as spam and report them to their ESP.

  • Content - The content of your emails can also affect their cold email deliverability. You must avoid certain words and phrases to ensure that your emails are received and not marked as spam. You might want to check our guide on subject lines for cold emails.

How To Fix Email Bad Deliverability?

If you're having trouble getting your cold emails into the inboxes of your intended recipients, you're not alone.

Fixing email deliverability issues can be tricky, and it's important to consider diverse factors to improve your chances of success.

Below, you'll find an outline of what you need to keep in mind as you work to improve your cold email deliverability:

Inbox Warm Up

Using an email warm-up tool is an excellent way to improve your email deliverability.

When you send emails from a new or inactive email address, it's necessary to gradually increase the volume and frequency of your emails over time to establish your sender reputation and avoid being marked as spam.

Email warm-up software automates this process by sending a series of test emails to increase your emails' volume and frequency gradually.

The email warm-up tool will also monitor your email deliverability and provide insights and analytics to help you identify issues and make adjustments as needed - this will save you a lot of time and effort compared to doing it manually.

In addition, email warm-up software often includes other features such as email verification, bounce handling, and reputation monitoring. These features will help you ensure your emails are delivered to the intended recipients' inboxes and avoid ending up in the spam folder.

Check out our email warm-up guide.

Write Personalized Emails

You may not be aware of this, but personalization can actually have a significant impact on your email deliverability.

When you personalize your emails by addressing the recipient by name or tailoring the content to their interests, you show them that you value their time and attention. This can increase the likelihood that they will engage with your email by opening it, reading it, and taking action.

But personalization isn't just good for your recipients - it's also good for you. Email service providers (ESPs) value positive engagement metrics, such as open rates and click-through rates, as an indicator that you're a trustworthy sender.

When your emails are personalized and engaging, you're more likely to see higher engagement metrics, which can help improve your sender reputation and ultimately lead to better email deliverability.

Monitor Bounce Rates Closely

When sending cold emails, email marketing, and newsletters, you need to be aware of two types of bounces: soft bounces and hard bounces.

A soft bounce occurs when the email is temporarily unable to be delivered to the recipient. This could be due to reasons such as a full inbox or a temporary issue with the email server. In most cases, the email will be retried for delivery over a period of time before eventually being marked as a hard bounce.

A hard bounce, on the other hand, is a permanent issue that occurs when you send an email to either a deleted email address or an invalid one. This could happen if the recipient has closed their account, changed their email address, or if you made a mistake in typing the email address. When an email bounces back as a hard bounce, it will not be delivered, no matter how hard you try.

It's important to keep an eye on your bounce rates because if both soft and hard bounce rates are too high, it can negatively impact your email deliverability and significantly decrease your domain reputation.

High bounce rates can be a sign to email service providers (ESPs) that your email list is outdated, low-quality, or that you're not following best practices. This could lead to your emails being flagged as spam and sent to the recipient's junk folder or, even worse, being blocked entirely.
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Make it Easy to Unsubscribe

It's important to remember that even if the content of your email is valuable, it's still considered unsolicited by many of your recipients. Not all of them will be happy to have received your email, and some may even mark it as spam, which can negatively impact your sender's reputation and ultimately hurt your email deliverability.

One of the best ways to avoid being marked as spam is to include an unsubscribe link at the bottom of your email. This gives your recipients the option to opt-out of receiving future emails from you, which shows that you respect their time and preferences.

Including an unsubscribe link is not only good for your recipients but also good for you. It allows you to maintain a clean email list by removing uninterested or inactive subscribers, which can improve your overall email deliverability.

It's also important to note that including an unsubscribe link in your cold email is not just a best practice, but it's also required by law in many countries. In the United States, the CAN-SPAM Act requires all commercial emails to include a clear and conspicuous unsubscribe link that allows recipients to opt-out of future emails.

Reach Out Only to Prospects That Match Your ICP

When it comes to cold emailing, sending emails to people who are irrelevant or don't need your service/product can be a recipe for disaster. Not only are you wasting your time and resources, but you're also risking your email deliverability and sender reputation.

When prospects receive unsolicited emails irrelevant to them, they are more likely to mark your email as spam or report it. This can lead to a high number of spam complaints, which can result in your email being blocked by email service providers (ESPs). High spam complaint rates can negatively impact your sender's reputation, making it more difficult for future emails to reach the recipients' inboxes.

To avoid this, sending valuable and relevant content is important. This means researching your target audience and tailoring your messaging to their needs and interests. By providing value and addressing their pain points, you're more likely to engage your recipients and establish a positive relationship with them.

It's also important to ensure your email list is clean and up-to-date, meaning regularly removing inactive or uninterested subscribers and avoiding purchasing email lists - purchased email lists are often low-quality and can contain invalid or outdated email addresses, leading to high bounce rates and spam complaints.

Tools to Check & Improve Cold Email Deliverability

When sending emails for marketing or sales, it's important to consider the email domain's reputation. A new email domain without a prior messaging history is considered cold, which may result in emails ending up in spam folders.

To avoid damaging the new domain's reputation, it's recommended to warm up the email domain to improve its credibility gradually. The same approach can also be used to restore an account's reputation, especially for an account with a long history of sending and receiving genuine emails.

While it's possible to use an email warming application to speed up the process, starting a new outbound sales campaign may require a faster approach - it's not advisable to attempt to fix email deliverability issues on your own.

Luckily, valuable tools are available to provide insightful information about your email domain and assist in fixing email deliverability problems.


GlockApps is a valuable service that provides users with inbox delivery and spam filtering testing. This service allows users to identify and fix deliverability issues before sending messages to their recipients.

The service offers a detailed report on how the email is delivered across major ISPs, what Gmail tab the email is delivered to, and whether an ISP blocked the message. This information can be extremely useful in fine-tuning email campaigns and ensuring messages reach their intended audience.

Further, GlockApps can alert users if SPF, DKIM and DMARC filters were triggered during email delivery, providing even more valuable insights into potential deliverability issues.


Postmark is an email delivery company offering its users an easy-to-use Spamcheck tool. With this tool, users can quickly and easily check the spam score of their emails by inputting the email's HTML code and headers into the dialog box. The lower the score, the better.

In addition to providing a spam score, Postmark offers valuable feedback on improving the email's quality. This includes suggestions on the quality of links in the content, sender domain authentications, image-to-text ratios, and overall HTML quality.

Postmark also provides a free API that can be integrated with Perl, C#, Ruby, and Python libraries for those looking to test spam automatically in their app.

Sender Score

Sender Score is a valuable tool for email marketers and newsletter senders looking to improve their email deliverability. The tool considers many of the most important factors that affect email deliverability, such as sender reputation.

One of the key features of Sender Score is its ability to provide a domain performance report as soon as you log on. This report includes ratings for your domain's IP addresses, giving valuable insights into how your emails perform across various email providers.

Spam filters consider the sender score, or reputation, a critical variable when determining whether an email should be accepted. While Sender Score does not provide specific advice on improving your score, it is still a valuable tool for identifying potential deliverability issues and taking steps to address them.

It's worth noting that building a good Sender Score from scratch can be quite challenging and may take time. However, when sending through an ESP, you typically use their domain ratings rather than your own, which can help improve your deliverability.


Cold email deliverability is a critical aspect of being successful in cold emailing. Your potential customers must see your emails; it is even more important not to send them to spam folders.

If you want your emails to be seen by your potential customers, then you must know how to improve cold email deliverability.

Many factors affect it, so it is important to remember them when sending your emails.

With the advice in this article, you can learn how to improve cold email deliverability and be sure that your emails are being received by the people they were sent to.
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