How to Improve Cold Email Deliverability

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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 that are 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 Is a Good Email Deliverability Rate?

Since the majority of 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 taking into account 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
  • the amount that fluctuates (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 aforementioned number.

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 you are trying to improve cold email deliverability, the first thing you need to do is take a look at the length of your emails. In general, shorter emails are better for cold emails than longer ones. While there is no specific length that will guarantee your email is received, shorter emails are generally better than longer emails.

  • Frequency - Another thing that can affect the cold email deliverability of your emails is the frequency of your emails. If you send too many emails at once, your recipients may mark your emails as spam and report them to their ESP.

  • Content - The content of your emails can also affect their cold email deliverability. To ensure that your emails are received and not marked as spam, it is important that you avoid certain words and phrases.

How To Fix Email Deliverability?

Fixing your cold email deliverability can be tricky. Below find an outline of what you need to consider.

Inbox warm up

A wide number of cold emailing software provide this feature, and the whole process happens through their system.

Personalized emails

Many people don’t know this, but personalization does indeed play an important role in deliverability.

This is a win-win for you as ESPs value positive engagement metrics deeming you to be a trustworthy sender.

Bounce Rates

There are two types of email bounces, soft and hard. They occur when cold emails do not reach their desired destination. If both bounce rates are too high, it can negatively impact the overall email deliverability and significantly decrease your domain reputation.

On the other hand, a hard bounce is when you send an email to either a deleted email address or an invalid one.

This is a permanent issue. The email will not get delivered, no matter how hard you try.

Make it easy to unsubscribe

Even if the content of your cold email is valuable, it is still considered unsolicited. Not all of your recipients will be happy to have received your email.

One of the best and simple ways to avoid being marked as spam is to include an unsubscribe link at the bottom of your email.

Reach out only to prospects that match your ICP

If you send sending emails to people that are not relevant or don't need for your service/product, they will be more motivated to mark your email as spam and to report them.

It is important to send valuable and relevant content only. Otherwise, people will mark your messages as spam.

Tools to Check and Improve Cold Email Deliverability

A cold email domain doesn’t have a record of prior messages, so it’s considered new. When you send out hundreds of emails from a fresh domain, many will end up in spam folders.
While this may damage your new domain's reputation immediately, cold domains can be warmed up to improve their credibility.

There are also some benefits to warming up existing accounts. The solution is to warm up the email domains.

It is also possible to restore an account's reputation by warming it up. An account with a long history of sending and receiving real emails has a very warm reputation.

In addition to repeatedly exchanging messages with family and friends, you've likely had a personal email account for years. You can use an email warming application to speed up the process, but if you're trying to start a new outbound sales campaign, you don't have years to do it.

However, trying to fix your email deliverability completely on your own is not recommended.
There are some very useful tools that you can use to get some very insightful info about your email domain.


GlockApps is a service that provides inbox delivery and spam filtering testing to help users determine and fix deliverability issues before sending the message to the recipients.

Users receive a report on how the email is delivered across major ISPs, what Gmail tab the email is delivered to, and whether the message was blocked by an ISP.

It also lets you know if SPF and DKMI filters were triggered.


Postmark is an easy-to-use email delivery company that provides Spamcheck.

You must insert your email's HTML code and all its headers into the dialog box. You'll get a score in seconds; the lower, the better. You'll get comments on how to improve your email, addressing:

  1. The quality of links in the content.
  2. The sender domain authentications.
  3. Image-to-text ratio (certain proportions trigger spam filters.)
  4. HTML quality in general.

To test spam automatically in your app, Postmark provides an API for free (even if you don't send your emails via Postmark). Perl, C#, Ruby, and Python libraries are also available for integration.

Sender Score

Sender Score is an alternative tool to consider. It considers many of the most important factors.

From the moment you log on, you can see the performance of your domain. You'll also see your domain's IP addresses' ratings.

Sender score or reputation is one of the most critical variables spam filters consider when determining whether an email should be accepted.

It does not provide any advice on improving the score, and it's also quite challenging to improve. You may not be able to build a good Sender Score from scratch immediately.

Of course, when sending through an ESP, you use their domain ratings, not your own.


Mailtrap Email Sandbox is the last option and the safest environment to inspect, test, and debug your emails.

With the Sandbox, developers can test, preview, and analyze email content before it is delivered to recipients' inboxes.

In addition to this, the Sandbox checks your domain's spam rating and checks it against the most common blacklists, then gives you the results.


Warm is an email warmup tool made by salespeople for salespeople.

We are dedicated to improving your email deliverability so you can hit all of your prospects' inboxes without worries about hitting spam.

Warm will accomplish this through real email engagement on the back end.

You can also use your own email copy to pre-send and engage with campaigns before sending them to your email lists.


Cold email deliverability is an important aspect of being successful in cold emailing. It is important that your emails are seen by your potential customers, and it is even more important that they are not sent to spam folders.

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

There are many factors that affect it, so it is important to keep them in mind 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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