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Cold Email Deliverability: Comprehensive Guide

27 min read
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If you have been in the cold emailing realm for a while, you probably already know the importance of cold email deliverability. You could spend hours on end beautifying your email content, but if your emails are landing in the spam or junk folder (or promotions tab), your entire purpose will be defeated. 

The thing about cold emailing is that it is different from sending emails to those who are subscribers. The risk of landing up in the spam folder is greater. In comparison, cold email deliverability is more difficult than opt-in email deliverability. 


Because you are sending unsolicited emails to people that don’t know you. The chances of a certain percentage of them marking your emails as spam are extremely high, even if you are offering the best product or service. 

This is indeed the reality for most cold emailers. Having your emails marked as spam can have a severely negative impact on your sender’s reputation and deliverability, now more than ever. So it is necessary to understand the ins and outs of email deliverability. 

Nearly 85% of emails received by users these days are regarded as spam. This is a shocking percentage! Email Service Providers (ESPs) and Internet Service Providers (ISPs) have put certain mechanisms in place to protect users from spammy content. 

This is why it is important to understand all the basics behind email deliverability, so your open, click-through, and conversion rates are not affected. Cold email deliverability is quite simple once you get the hang of it. One must understand the basics, technicalities, and best practices involved to yield favorable results. 

This guide deep dives into everything you need to know about cold email deliverability. Optimizing for improved deliverability is an absolute must to ensure your emails land in the primary inbox of your prospects. 

Before we get into the technical stuff and best practices, let us first understand what the concept of email deliverability means. 

What Is Email Deliverability?

In very simple terms, email deliverability refers to the ability of your email to reach the recipients’ primary inbox as intended. The reason email deliverability is becoming a hot topic is that in recent times it has become increasingly complex to reach the inbox of your prospect due to the rise of smarter spam filtering technologies. 

The average email deliverability rate amongst all ESPs is around 85.3%. The remaining percentage are emails that are either sent straight to the spam folder or completely blocked by mailbox providers. 

Email deliverability is both an art and a science. In order to achieve the results you sought, you need to track your deliverability daily. Here are a few baseline metrics to keep in mind when tracking deliverability: 

  • A bounce rate higher than 3% is a cause for concern 
  • Most ESPs consider 95% (or higher) to be a good delivery rate 
  • If your spam rate exceeds 0.08% then there is a high chance you risk losing your account

As a salesperson or marketer, you need to put in the time and effort for your outreach campaign to succeed. 

By the way, email deliverability is different from delivery rate (also known as acceptance rate). 

Email delivery rate refers to the number of emails that have been accepted into the Mailbox Providers’ (MBP) servers. If the email address is faulty, then your emails will bounce and impact your delivery rate. 

Email deliverability comes into play after the acceptance of the email from MBPs. Deliverability determines where the email will land in the inbox based on domain reputation, sender reputation, and domain setup. If an issue is detected with any of these factors, your deliverability rate will take a massive hit.

Why Is Email Deliverability Important?

Email deliverability is often overlooked by several marketers and salespeople. Deliverability should be your best friend! One of the main reasons behind this is that email is known to have the highest ROI as compared to any other digital marketing channel.

For every $1 spent on cold emailing, a return of $42 is noted. 

  1. Deliverability plays a huge role in seeing profitable numbers. Think of email deliverability as the foundation for an increased ROI. Spending a considerable amount of time on setting up your domain, collecting email lists, and writing compelling content will all be in vain if the emails are not being seen by the recipients. 
  1. Inboxes of recipients are getting cluttered i.e. the competition is increasing. As a result, email deliverability is pivotal in getting a return on your investment. If emails are being relegated to the spam folder, or you are blocked by certain MBPs because of poor deliverability, then you cannot obtain any ROI.

    Good email deliverability ensures healthy prospect relationships, which help you gain more conversions and ultimately stay ahead of the competition; largely because reaching the intended recipients’ inbox is an important growth metric for your campaign. 
  1. MBPs are placing their focus on recipient engagement more than before. Engagement metrics like opens, clicks, and replies all influence your deliverability.

    Negative engagement metrics like user complaints, deletion of emails without opening them, time spent reading, and links clicked are also taken into account by MBPs. Email engagement can be regarded as a ‘trust meter’.

    If you send out emails that receive positive engagement rates, MPBs will view you as a credible and trustworthy sender thus rewarding you with improved deliverability. 
  1. Lastly, email deliverability allows you to track and understand user behavior in depth. Metrics such as the time the email was opened, the number of active subscribers, how they interacted with your emails, etc help marketers/salespeople enhance user engagement and gather qualified leads. 

The Negative Impact Of Compromised Email Deliverability

What happens when you are facing poor email deliverability? Here is a side-by-side comparison of good vs poor email deliverability to help you understand the negative and positive impacts. 

impact of email deliverability

Hopefully, by this point, you understand the importance of investing time and money into achieving proper email deliverability. In the next section, this guide will delve into some of the best practices you can use to maximize your deliverability. 

Let’s start with first understanding ‘Sender Reputation’.

Sender Reputation

Your sender reputation is a score given to your domain by Email Service Providers (ESPs) in an effort to show that they see you as a trustworthy sender. When you have a higher score, ESPs are more likely to trust you with future emails and will send your emails to your recipients’ primary inboxes. 

In case you have been given a lower score it does not necessarily mean your emails will be sent to the spam folder; however, the likelihood of them landing up there is much higher. This means there is a chance your outreach may not yield desired results. 

The sender reputation score is based on factors such as the quality of contacts, content quality, and engagement metrics of previously sent emails from your domain. 

improve email deliverability with a good sender reputation

If your sender reputation drops too low below a certain point, ESPs can block your emails completely from landing in the primary inbox of the prospect or the email landing anywhere in the inbox. 

(If you are unsure about sender reputation, there are various tools available online that can check it for you. I recommend using Saleshandy, they provide information on your email health score which consists of email age and email authentication checks.)

So, how do you maintain and increase your sender reputation? 

  • Maintain low bounce rates: Keep cleaning your email lists regularly. If someone emails you back saying they are not interested or if a prospect has never opened or replied to your email remove them from your list entirely. 
  • Keep your complaint rate low: When a recipient marks an email as spam, it is registered as a complaint. ESPs take spam complaints very seriously and have a low tolerance for them. Ideally, your complaint rate should be below 0.01%. Remove email addresses from your list that marked your email as spam so you don’t bother them. 
  • Ensure you properly format your emails and share valuable content: Improper formatting and content can set off alarm bells for ESPs. Inboxes of users are already cluttered, so one must send valuable content that is relevant to them.

    In your email content ensure, that your HTML is properly formatted, the unsubscribe link is legible, your content is compatible with mobile devices, and your email is compatible with all major ESPs. 
  • Watch out for spam traps: Spam traps are used by blacklist and mailbox providers to identify spammers to block their domain. It operates as a real email address and does not belong to a real person (it is run by ESPs). Most purchased lists have a spam trap on there, so avoid those altogether. 
  • Blacklists: If you get blacklisted by an ESP then you cannot send any more emails. And it is not easy to get off that list either. You usually land up on a blacklist if you engage in spammy email practices, launch campaigns using purchased lists, or hit a spam trap. (You can check if you are on the blacklist using this tool – MX Toolbox Blacklist)

Ideal Cold Email Deliverability Rate

It is hard to determine an exact figure on what entails an ideal deliverability rate as the majority of ESPs are secretive about their email data. 

However, by taking into account deliverability metrics, we can draw up a rough estimate. Here are the main metrics you need to focus on: 

  • The percentage of emails landing in the primary inbox vs. the spam folder 
  • The percentage of emails delivered 
  • The percentage that is bouncing (both hard & soft bounces)

To experience success with cold emailing, an overall deliverability rate of 95% is recommended. Anything lower than the previously mentioned figure and you will start incurring problems. 

One important metric to pay close attention to is the bounce rate. A well-targeted cold emailing campaign should have a low bounce rate especially if you have already pre-verified your email list. Aim for a bounce rate of 2% to 3% or less. 

If your bounce rate is higher than that, then you need to spend more time validating email addresses (pro tip: use email verification tools). 

To keep an eye on the metrics mentioned above, you can use cold emailing tools like Saleshandy that provide users with in-depth analytics on their ongoing cold email campaigns. 

Minimum bounce rate for maximum email deliverability

The reports provided show you open rates, bounced emails, reply rates, the number of clicks on links, and unsubscribe rates.

Cold Email Deliverability—The Basics

Email deliverability is a meticulous process that requires a step-by-step procedure to ensure landing in the primary inbox. Simply typing up an email and hitting sent is not enough for a successful delivery. 

There are a myriad of factors determining if your email will be successfully delivered to the inboxes of your recipients. Each ESP uses different algorithms for its filtration system, but at the crux of it all, they are functioning in a way that ensures each message they deliver is safe for their recipients. 

However, they are a few key factors that affect deliverability (some technical) that can aid in building a solid foundation for inbox placement. 

In simple terms, once you hit send, ISPs and email servers of your recipients have to go through a lengthy checklist before providing you access to their inbox. In this section, we will discuss that checklist and what you need to look out for in order to not get flagged. 

  • Technical Authentication – (DKIM/SPF/DMARC) 

When you create a new domain, you need to ensure all your technical foundations are in place. Email authentication acts as an extra layer of security differentiating your domain from spammers and phishers.

It also proves to ISPs that your email is from you, and not forged by someone else. ISP’s value domains with proper authentication as it makes it easier for them to identify you as a legitimate sender and blocks harmful uses of email. 

There are three standard email authentication methods used: 

  1. DKIM (Domain Keys Identified Mail) 

DKIM is an email authentication standard that helps detect malicious modification of the email in transit between sending and receiving mail servers. Without this layer of security, there is a risk your email can be tampered with and have its contents changed. Spam filters generally won’t send risky emails to anyone’s inbox. 

2. SPF (Sender Policy Framework) 

A Sender Policy Framework (SPF) allows your organization to clearly specify the users that are allowed to send emails on behalf of your domain. SPF records are usually added and published in your Domain Name System (DNS). 

When you hit send, MBPs perform an SPF check. During the check, they verify the SPF records by searching for the domain name listed in your DNS records. 

3. DMARC (Domain-based Message Authentication, Reporting, & Conformance)

DMARC is the latest addition to email authentication standards. In layman’s terms, DMARC unifies SPF and DKIM authentication together into one common framework to ensure mailbox servers of the recipients that the email coming in from your domain is authenticated against SPF and DKIM. 

Learn how to configure your DMARC by watching the video below: 

Having all three of these email authentication protocols in place is essential for successful email deliverability. If you don’t set these up, your emails will end up in the spam folder. 

The majority of hosting servers and ESPs will have a set of instructions on how you can set these up. 

If you want to check your DNS records, then you can use this DNS Lookup Tool

Optional Extra Layer of Authentication: BIMI (Brand Indicators For Message Authentication)

BIMI acts as an extra layer of email protection whilst simultaneously building brand visibility. This emerging email standard displays your brand logo in your authenticated message. Through this simple visual verification, recipients are able to recognize and trust the emails you send (and that trust leads to fewer spam complaints).

BIMI was created by the Authindicators Working Group to help prevent fraudulent emails and establish trust with email receivers. BIMI is a text record that lives in your sending servers and works alongside SPF, DMARC, and DKIM to double verify to email clients that it is indeed you sending the email. 

BIMI also supports deliverability by increasing user engagement and showing ESPs that you already have existing security protocols set up and in place. 


Source: Moosend

  • Start with lesser emails 

This point is especially important for those that have newer domains (less than 6 months old). One of the golden rules of cold emailing is to showcase human behavior as much as possible, if servers detect any bot-like behavior they may think your account is spam. 

When you are first sending out emails, the first and foremost thing you should do is check your email age. How old is your domain? Have you used it before? Newer domains are more susceptible to being flagged as spam as ESPs don’t have any previous data to determine whether you are a trustworthy sender or not. 

Additionally, if you send out identical mass emails it will trigger the ‘spam filter’. And when that happens your emails will not land in the primary inbox of the recipient. 

So in order to curb this issue, you can opt for an email ramp-up. Email ramp-up entails sending out a smaller number of emails and then gradually increasing the number daily. There are many cold email software that have this feature. 

Saleshandy’s email warm-up feature allows you to connect your domain, send emails on your behalf, and engage with them from their own trusted accounts. This way, ESPs see that your newer domain is trustworthy and is receiving the engagement to differentiate it from a spam account. 

  • Spam reports (or spam complaints)

A spam complaint occurs when a recipient marks your email as spam by clicking on the ‘mark as spam’ option in their email client. 

ESPs take these complaints extremely seriously as it indicates recipients are not happy with your email. If your complaint rates continue to increase, there will be a drop in the sender reputation making it difficult for you to land in the primary inbox. 

As mentioned previously in the sender reputation section of this guide, try to keep your complaint rate less than 0.01%. If a user marks you as spam, immediately remove them from your list to avoid any further complaints. 

  • Spam triggering verbiage 

Yes, spam triggering verbiage exists. 

Spam trigger words are phrases that ESPs flag as spam with the suspicion that the email content is of a fraudulent and malicious nature. When an email is sent out it is run through a filter of sorts, and if any spam triggering verbiage is detected the email is routed to the spam folder. 

Generally, these words and phrases overpromise recipients an offer that is unrealistic in the hopes of gaining sensitive information. A lot of marketers and salespeople tend to use these phrases in their subject line inadvertently. A study by Ortto found that 14.7% of emails get caught by spam filters.

Here are some words and phrases that are regarded as spammy by ESPs: 

  1. Buy now!
  2. Click here 
  3. Hurry up 
  4. XXX
  5. Offer expires 
  6. Urgent 
  7. Best price 
  8. Free gift 
  9. Prize 
  10. Promise you
  11. 100% free

Choose your verbiage carefully. In addition to words and phrases, avoid excessive use of too many bolded words, emojis, all caps, special characters, and strange fonts.

  • Inserting too many links and images

Inserting one too many links and images is a surefire way of getting caught by spam filters. It is best to only include a maximum of 2 links in your email content. Maintaining a good image-to-text ratio (40% image and 60% text) will keep you away from any deliverability issues. 

By the way, if you are still in the warming-up stage, then start off with no links or images in your email content to be on the safer side.

  • Blacklists

We talked about blacklists before and how they affect your sender reputation. To refresh your memory, a blacklist is a real-time list that identifies IP addresses or domains that have a history of sending spam emails. Nearly all ESPs use this blacklist to protect their users against spam. 

The IPs and domains of spammers are put on this list if they continually send out mass spam emails. If the recipient’s email or ISP utilizes blacklists, the IP of the incoming sender is checked against this list.

If the sender’s IP is listed on the blacklist, the email will automatically be rejected and will never get delivered to the recipient’s inbox. The image below showcases how blacklists interact with an email. 

How backlisting effects email deliverability

Source: Spamhaus

If your open rate has suddenly dropped out of nowhere, it’s likely that you have been blacklisted. Sometimes your ISP will notify you that you have been blacklisted, but generally, most people have to do a manual check. 

Here are the two most common services that compile anti-spam lists: 

  1. The SpamHaus Project 
  2. SpamCop

If your email server IP or domain is found on the blacklist, your first step should be to figure out their unlisting process. Sometimes all you need to do is prove that you are not a bot or spam account. It is also important to understand why you were placed on that list in the first place. 

There are some blacklists that don’t have an unlisting process and remove your IP automatically after a certain amount of time, only if you stop acting like a spammer. Being taken off the blacklist isn’t a cause for celebration because you are on parole, and your email sending habits will be under close monitoring.

How To Increase Cold Email Deliverability? 

By now you must have a clear understanding of how email deliverability works and the technical mechanisms at play in the background. In this section, I will be sharing a few additional factors that can influence your email deliverability.

The tips mentioned below will help you increase your deliverability long-term and benefit your future cold outreach campaigns. 

1. Inbox warm-up

Inbox warm-up is especially important for new domains and email addresses. The act of warming up your inbox entails, sending out emails from the new account and receiving high open, reply, and engagement rates. A wide number of cold emailing software provide this feature and the whole process happens through their system (no manual sending or waiting for replies needed).

2. Use a cold emailing software (not email marketing software)

Cold emailing and email marketing have different needs, something marketers and salespeople need to understand. Email marketing software usually has an HTML editor to design emails, whereas, cold emailing software has a normal plain text editor.

Use a cold emailing software that has features like inbox warm-up, email tracking, merge tags, automated follow-ups, A/B testing, custom domain tracking, email engagement analytics, etc.

3. Personalize emails

A lot of people don’t know this but personalization does indeed play an important role in deliverability. First, here’s the technical explanation—when you send out identical emails, it will trigger the ‘spam filter’, automatically routing your email to the spam/junk folder.

The other quantifiable explanation—in two simple words, engagement rates. When you personalize email content, prospects will be more inclined towards opening, clicking on, and replying to your email.

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

4. Bounce Rates (hard and soft bounces)

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. 

A soft bounce is when the recipient’s email server rejects the incoming email due to a temporary issue such as the inbox being full, the size of the email being too large, server outage, etc. 

A hard bounce, on the other hand, 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. 

The accepted bounce rate ranges from 2% to 5%. To avoid high bounce rates, regularly verify your email list and remove all inactive or invalid email addresses. 

5. Keep updating your prospect list

Your prospect list will grow as you acquire new customers or have more email subscribers. Having a targeted and healthy list of recipients will work better for overall deliverability.

It is also important to send valuable and relevant content only, otherwise, people will mark your messages as spam (and if they ignore them, this will hamper your engagement rates). 

Keep updating your prospect list daily. Whenever you incur a hard or soft bounce, remove them immediately. Use email verification tools to further verify email addresses or find the correct ones. 

By the way, if your email list grows at a suspiciously high rate, ISPs and ESPs will suspect a list has been purchased. In general, it is not recommended to buy email lists. 

6. Make it easy to unsubscribe

Even if the content of your cold email is valuable, it is still regarded as an unsolicited email. 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 (opt-out) link at the bottom of your email. 

A lot of senders make the mistake of hiding or burying the unsubscribe link. Sure, in theory, this sounds like a solid way to prevent someone from unsubscribing to your future emails, but ultimately this will cost you. 

What alternative is the recipient left with? Marking you as spam. Ensure the unsubscribe button is easy to find and legible. 

How Do Engagement Metrics Effect Email Deliverability?

Are you aware of how your recipients are interacting with your email? 

Most email senders are only privy to two engagement key metrics, open and clicks, through which they gauge the reaction of their recipients. 

However, mailbox providers have widened their net of actions and metrics to use when measuring engagement. Because of this, recipient engagement is now placed at the forefront of email deliverability. 

The infographic below carefully explains the positive and negative reactions that mailbox providers use to measure engagement. By reading these it will become clear to you what actions mailbox providers value. 

Email deliverability

Tools To Improve And Check Your Email Deliverability

1. Saleshandy

Best cold email deliverability tool

Saleshandy is a cold emailing software equipped with features that boost deliverability while tending to all your emailing needs. Through the use of Saleshandy’s superior features, your outreach campaigns will achieve maximum deliverability as well as high conversion rates.

Listed below are the much needed email deliverability features: 

Email Health Score 

Email health score

The email health score feature allows you to check the overall score of your domain. Saleshandy automatically runs technical authentication checks for you to ensure you have all the security mechanisms required.
If you do, it estimates a score for your domain to determine its validity for launching cold email campaigns.

Beyond that, each security mechanism is explained via a YouTube video with proper how-to steps to attain effective deliverability. If you are struggling with deliverability, the option to talk to deliverability experts is also available. 

Inbox Warm-Up 

cold emailing 2022

The inbox warm-up feature allows you to warm up your new domain so it can be ready for high-volume campaigns in the future. You can add all of your domains to Saleshandy, configure all the settings, then click on enable and that’s it!

Everything else will be taken care of Saleshandy and within a few months, your domain will be ready for mass email sending. Saleshandy uses AI-powered algorithms to mimic human-like interactions to make it look legitimate.

Emails are replied to, marked as important, removed from spam, and engaged with so ESPs trust your domain and grant you maximum deliverability. 

Merge Tags 

Personalization and deliverability go hand in hand. With Saleshandy, you don’t have to worry about manually personalizing each and every email. Instead, with the help of merge tags (eg: {{first name}} {{last name}} {{company name}} {{designation}} {{city}}), you can mass personalize your email content and subject line without any hassles. Data can directly be imported from sheets with up to 30 custom fields. 

Email Age 

The email age feature lets you know if your domain is old enough to start sending high-volume mass cold email campaigns. Domains that are less than 6 months are usually more vulnerable to spam filters, especially if you intend on sending out a large number of emails.

This feature automatically lets you know if your domain is old enough for achieving good deliverability.

AI-Powered Email Assistant And Spam Words Checker 

email deliverability test

The email assistant feature helps you write impeccable email copy taking into account personalization, the number of spammy verbiages, links, and the length of the subject line.

The AI-powered assistant automatically generates smart suggestions for the user to write the perfect email for prospects whilst keeping the best deliverability and cold emailing practices in mind. 

2. Postmaster Tools

best cold email software for deliverability

Postmaster Tools is a free tool by Google that allows you to track data for mass email campaigns and find information about your domain. It shows data such as, spam rate, sender reputation, IP reputation, delivery errors, and performance diagnostics. 

To use this tool, add and verify your authenticated domain and gain access to email traffic and performance analytics. 

3. Spam Checker (By Mail Meteor)

how to increase email deliverability

Spam Checker is a spam word checker by Mailmetoer that detects spam triggering words in your email content. It automatically highlights words that should be removed and rephrased in your email body. It detects spam words and categorizes them into 4 categories, unnatural, shady, overpromise, and urgency.

Get here: 11 Email Deliverability Tools to Land In The Primary Inbox

Wrapping up 

Deliverability holds the key to the success or failure of your cold email campaign. If you want advantageous results then you need to keep a keen eye on your deliverability. A large percentage of marketers and salespeople focus too much on other factors of their campaign when in actuality email deliverability should be placed at the top of their list. 

If your emails are not making it to the recipient’s inbox, then what’s the point of putting in all that extra effort in other areas? You won’t see any results this way. 

Follow the practices and tips mentioned in this guide before you launch your campaign and  diagnose any bottlenecks that may arise in the future. 

Remember, email deliverability is paramount for a successful cold email campaign. Once your ESPs can ensure email deliverability, cold emailing will become a lucrative avenue to generate business from prospects. 

Skyrocket your conversion rates with cold emailing

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