Understanding Email Deliverability: A comprehensive guide for cold outreach to increase sales

According to Demandsage 2024 report, 347.3 billion emails were exchanged every day and it has been predicted that it will increase to 392.5 billion by 2026. These stats, tell us that emails continue to be a vital communication and marketing channel. But let me inform you, 85% of the emails sent land in the spam category meaning most of them won’t ever be opened. This actually defeats the purpose of email marketing, all the planning and execution goes to waste. In short, customer relationships suffer and revenue is lost.

Then what’s the solution?

The answer is to improve email deliverability, through stronger security protocols and authentication methods. It has been observed that brands that take measures to verify their sending practices and content, see higher inbox placement rates. Once emails reach the inbox, open and click-through rates also improve. For instance, legitimate emails enjoy roughly a 90% inbox placement rate compared to 5% or less for spam. Brands must make deliverability and security a top priority to drive returns on email marketing. 

This guide will explore best practices to safely deliver your messages while maintaining compliance and subscriber trust.

What is email deliverability and why should you care?

Email deliverability refers to the ability of a sender to successfully deliver an email to a subscribed customer, ensuring that it ends up in the recipient's inbox folder. It has been confirmed by Earthweb’s reports that 99% of email users check their inboxes at least once every day meaning these emails have a higher chance of being opened.

Now, many people might compare email deliverability to email delivery which is not the same. While email delivery ensures your messages get sent out, deliverability focuses on whether those emails arrive safely at their destination without being caught in the spam filters. Your chosen Email Service Provider such as Gmail, Yahoo Mail, and Outlook will check the email for flagged and blocked content before sending them across.

Understanding the factors that influence deliverability is crucial for marketers to build an effective campaign strategy that will yield tangible results. A well-made email deliverability plan takes care of various aspects, ranging from sender authentication to content personalisation to list hygiene. By implementing this plan effectively, you can expect to achieve the following results.

Increased engagement

Emails that avoid spam traps and junk folders naturally get more visibility. Similarly, Opt-in subscribers, people who have voluntarily subscribed to your content, will want to hear from you, a brand they trust. 

Improved conversion rates

Inbox placement signals authority to subscribers, making them more likely to open and click emails ultimately leading to more chances of conversions.

Enhanced brand reputation

Consistently reaching the inbox builds a positive brand outlook. Subscribers equate your reliability with quality products or services. This drives referrals and loyalty over the long term.

Understanding email infrastructure

Before we get into inbox placement strategies, let’s understand the important components of email infrastructure. To land in the inbox, you need to have a good understanding of concepts such as SMTP, mail servers, and DNS, no matter how many emails you're sending or how often. Building a strong infrastructure foundation is the first step towards ensuring that your emails reach their destination every single time.

What is email infrastructure?

Email infrastructure refers to the path that messages take on their way to getting delivered to the recipient, and it greatly influences whether they land in the inbox or not. Email infrastructure uses several technologies for the worldwide transfer of electronic messages. At the foundation level, we have the Simple Mail Transfer Protocol (SMTP), which acts as the communication bridge between mail servers, ensuring that emails are directed to the right recipient inboxes.

Let us check out the nitty-gritty of email infrastructure.

What are SMTPs and how do they work?

Think of Simple Mail Transfer Protocol (SMTP) as an energy-providing generator that directs billions of emails per day to subscribers. It establishes the connections between the mail servers of senders and receivers.

How does SMTP know which mail server to send mail to?

This is where MX records come in. Every domain has a Domain Name System record and an MX record is a type of DNS record that is responsible for accepting incoming emails for a domain. So when a sender sends an email, the SMTP is triggered and the MX record tells SMTP exactly which mail server to communicate with to deliver the email to the recipient domain. Once the recipient mail server's identity gets verified with the help of the MX record, SMTP pushes the message across networks until it reaches the designated inbox.

Managing DNS records

Domain Name System records are used to translate domain names into numerical IP addresses that computers can understand. Only proper DNS records allow emails to be correctly routed to their destination.

Now that we are familiar with the email infrastructure we will move on to exploring what happens behind the scenes when a message gets sent. 

How do emails get delivered?

As email sender or receiver, the only thing that we are concerned about is whether our marketing campaigns bring in results or whether we receive the designated emails, respectively. But, how do we receive the correct email all the time, the process is mentioned below.

The journey an email takes to land in a subscriber's inbox involves an elaborate process. When you hit send on an email message, the message leaves and avoids being caught in the spam filters, hopefully reaching the inbox. Let’s understand the steps involved.

The email sending process

The sending process begins automatically in a series of steps when a campaign is triggered to be sent.

• You write an email and send it from an Email Service Provider (ESP) such as Gmail, Outlook, AWS SES etc. Check top 10 cold emailing tools for 2024.
• The outgoing mail server receives and sends the email using the SMTP protocol and DNS records. 
• The email is then handed off to the receiving mail server, which is authorised through Sender Policy Framework (SPF) records. 
• The receiving server's spam filters analyse the content of the email. If the email is up to the mark, it lands in the inbox, but if it's flagged as spam, it ends up in the spam folder.

Basic checklist to make it to the inbox every time

• Stick to the guidelines set by your Internet Service Providers which affect the sender's reputation based on the score.
• Keep an eye out for sudden drops in email deliverability, which could be a sign of potential blocks.
• If you find yourself blacklisted, submit a request to get delisted as soon as possible.
  

By understanding how Internet Service Providers (ISPs) work, you can avoid your emails getting trapped in spam filters.

Spam Filters

Spam filters automatically detect and redirect potential junk mail to the spam folder, keeping inboxes clean. They look out for suspicious content, a poor sender reputation, or a lack of authentication. If any of these signals are triggered, your message might end up in the spam folder without the recipient knowing. To avoid this, ensure your content is clear and relevant.

Whitelisting

Whitelisting means your emails clear the spam checks and go straight to the recipient's inbox. Big email service providers (ESPs) usually have a spot on the ISP whitelists by default because they follow strict protocols. But for smaller brands, getting whitelisted can be a game-changer, especially when you're warming up a new IP address.

Blacklisting

It is a practice where all emails from identified IPs or domains are completely blocked. This means that even legitimate senders can end up on these lists due to minor mistakes or falling into spam traps. However, this issue can be avoided by regularly monitoring and promptly requesting removal from these lists.

Even when you follow these protocols you might end up in the spam or promotional folder which is disheartening. To ensure your emails don’t end up in spam, we will dive deeper into the factors that influence the email deliverability rate. 

What are the reasons behind poor email deliverability?

Poor email deliverability significantly affects your company’s email domain reputation meaning how much credibility is placed in your domain by an email service provider. This leads to all your marketing efforts going down the drain. There are several issues that threaten deliverability rates, from technical glitches to messaging errors. 

Let us understand them carefully to avoid damage inbox placement:

Sender reputation and behaviour

• According to the emailtooltester, 14.3% of emails are in spam or promotion folders. A sender's reputation is estimated with a numerical value ranging from 0 to 100, if your score is above 89%, it means your content is wanted and you are doing well but in case it is below 70% then your Internet Service Provider (ISP) will either flag your content or block it altogether.
• This decision will be based on an assessment done on the type of emails you send, how frequently, and the kind of words you use, for example, messages with words like “Buy 1 Get 1 Free”, “100% off”, “Only 24 hours left” and “Flat 10% off”, these are some of the words that trigger spam filterings. 
• Similarly, suspicious engagement behavior like sudden spikes raises red flags leading to ISPs.
• We’ll talk about warming up the IP address later in this guide to understand how you can grow gradually and escape any suspicion.
  

List quality and engagement

• Maintaining a hygienic email list is very crucial, if your email list is filled with invalid, inactive, or unengaged addresses, it signals apathy for the subscriber preferences. These signs categorise senders as spammers rather than legitimate businesses.
• If the subscribers are not opening your emails or marking them as spam or have unsubscribed from your content, this becomes a problem. You would need a complete makeover so that you are not ending up in spam.
• You should aim for a 20% open rate meaning the number of emails opened by recipients and a 1% clickthrough rate, links clicked by recipients mentioned on your emails.
  

Authentication methods

• If you want ROI on your email campaigns then you need to authenticate yourself as a sender. The lack of valid authentication makes it impossible to confirm the sender's identity. Often, unsigned emails skip straight to junk folders regardless of content quality.
• You can properly implement SPF, DKIM, etc. verifying sources and ensuring deliverability. We’ll discuss these in detail in the further sections.
  

Email content and triggers

• The emails you send to your subscribers should be free of alarming content elements that trigger spam filterings such as sensational subject lines, clickbait offers, suspicious links or attachments, and overuse of sales copy or graphics.
• For example, a subscriber may generally trust receiving emails from a clothing retailer they often buy from. However, if that retailer sends an email with dramatic subject lines, excessive sales language, or irrelevant products, it reduces the sense of relevancy despite the existing trust.
  

Technical issues

• However, technical issues such as damaged DNS records, unresponsive servers, or blacklisting can cause disruptions in email delivery, regardless of the quality of the content. To avoid these problems, it is essential to closely monitor and maintain the infrastructure.

How can you improve your email deliverability?

Now that we’ve explored the various reasons that threaten email deliverability, let’s shift the focus to solutions. If you want to achieve a high email deliverability rate work together with platform protocols, and infrastructure safeguards, maintain high-quality lists, and ensure relevant content. It's all about making sure your messages reach their intended recipients. It might sound hefty to take care of so many aspects but marketers have a mixed path to resolve them and we’ll discuss them in detail.

Building your sender reputation

• To establish a positive reputation as a legitimate sender, it's important to take it slow and gradually increase your email activity. Instead of bombarding recipients with a large number of emails right from the start, send only a limited amount each day. By doing so, you'll be able to warm up your IP address and improve your sender score.
  
• This approach will help internet service providers (ISPs) recognise you as a trustworthy sender, reducing the chances of being blocked or flagged.
  
• Avoid email bounce rate, meaning the percentage of your emails not being delivered to the recipient, by collecting double opt-in email addresses. If your bounce rates are above 3 percent, this is a red flag.
  
• When subscribers opt out of receiving any email, monitor spam complaints and unsubscribes via feedback loops in ESPs and make sure to not send the unsubscribers any further emails.

IP reputation

• Every email sender has an IP address, which is basically a numerical identification code for a server computer. Large email providers look at the reputation of these IP addresses and the domains they are associated with to help determine whether an email should go into the inbox or not.
  
• The reputation of an IP address or domain is like its "track record" for sending emails.
  
• Make sure to opt for dedicated IP addresses. A shared IP means other senders also use it, so their actions also influence your reputation. Dedicated IPs involve only you but you will have more responsibility to maintain the reputation yourself.
  
• Low reputation is harmful as major mailbox providers like Gmail will equate this to higher spam risk and send those emails to the spam folder regardless of the content.

Authenticating your emails

Email authentication verifies your identity as the genuine sender so emails reliably reach recipient inboxes instead of getting marked as spam. The three primary methods are SPF, DKIM, and DMARC.

Sender Policy Framework (SPF)
It functions by allowing you to publish approved sending IP addresses. When emails are sent, the receiving server checks that the sending IP matches the one listed in the SPF record of the domain. If the IP is found in the permitted list, the sender is authenticated as legitimate. If not, the mail may be flagged as spoofed. SPF prevents imitated identities from sending spam or phishing emails by verifying valid sending servers.

DomainKeys Identified Mail (DKIM)
It inserts encrypted signatures with details like your domain, headers, and content into emails. The receiving server decrypts this to verify your domain. If it validates successfully, the domain is confirmed as genuine. DKIM prevents impersonation attacks and builds sender credibility.

Domain-based Message Authentication, Reporting, and Conformance (DMARC)
It works hand in hand with SPF and DKIM policies. These policies are important in informing email receivers about how you want them to handle unofficial emails that don't comply with your set policies. By implementing DMARC, you gain the ability to manage your email flow in a more detailed manner, such as rejecting failed emails to prevent spamming abuse. Leading email service providers offer user-friendly tools to generate the complex syntax of authentication records tailored to your configuration.

You should make sure to validate that your outgoing emails are properly authenticated using SPF, DKIM, and DMARC standard protocols and are not in a spam database. 

Managing your subscriber list

• Regularly remove invalid email addresses that bounce back as undeliverable. Also, delete subscribers who marked emails as spam or unsubscribed. This keeps your list accurate.
• If subscribers have not opened emails for 6 months or more, remove them. Double-check all new signups to confirm valid and active inboxes. You can set up 2-step verification to guard against fake or misspelled addresses so that the receiver actually confirms that they want to receive mail from you.
• The other mistake you should avoid is buying email lists of unknown origin because typically it backfires with low engagement and high complaints.

Optimising your email content

• According to a GetResponse 2022 report, emails with images have 10% higher chance of being opened.
  
• Images should be used modestly, and text should be written in short paragraphs that are easy to scan. This is readable on all devices and accommodates different reader preferences. Avoid using misleading language, over-the-top claims, and aggressive promotions. Even with permission-based sending, these elements can trigger spam filters.
  
• Before final sends, check how the email displays, if links work properly, and whether it triggers spam filters across different email clients. Offer your subscribers relevant, personalised content to enhance engagement leading to higher open and click rates. 

Some advanced deliverability tips

• Use DNSSEC to secure your domain's DNS records. It adds digital signatures to prevent hacking of the records. This shows recipients your domain is protected against attacks.
• Get a dedicated IP address just for your email instead of sharing an IP. If others on a shared IP send spam, you can get blocked too. With your own IP, you control the reputation.
• Make your website secure with HTTPS encryption. An unsafe site hurts your domain's trustworthiness. Recipients may doubt emails from you. Keep your site malware-free too.

How does Gmail support email security for all users?

To fight complex email threats, Google and Yahoo have come up with new sender guidelines for high-volume bulk senders to authenticate their emails with rules like:

• Let users unsubscribe easily
• Send only wanted content and avoid spam
• Authenticate emails
  

These basic email hygiene steps will close gaps used by attackers posing as bulk senders. While many authentic senders already follow some rules, these new requirements will help all email users by better-protecting inboxes. But keeping email safe needs ongoing teamwork and watchfulness against changing threats across the email world.

How to keep a check on your email deliverability?

• Setting up feedback loops within your email service provider will prove to be of big help. This allows you to track hard bounces, complaints, unsubscribes, and other signals. By analysing this data, you can identify any problems with your email list or deliverability
• Another useful technique is conducting A/B testing. This involves sending different versions of an email to a small test group before sending it out to everyone. By comparing open and click-through rates, you can optimise your content and make it more engaging.
• Check blacklists to ensure your IP address or domain is not blocked, and whitelists to potentially improve inbox placement. Take steps to get removed from blacklists if needed, with tools like Spamhaus and MX tools.
• Leverage Postmaster Tools like those offered by major email providers to monitor reputation and prevent deliverability issues such as Google Postmaster.
• Test inbox placement by sending emails to accounts on major email providers to confirm your mail is arriving in the primary inbox rather than spam or other tabs with tools such as Messagebird's inbox tracker.
• Monitoring your sender score is another important step. Services like SendGrid assign a numerical reputation based on engagement and complaints. It's essential to maintain a high sender score, as low scores can negatively impact your future deliverability.
• Lastly, don't forget to audit your email authentication protocols. SPF, DKIM, and DMARC are important authentication methods that help confirm proper setup. Lack of authentication is a major cause of emails ending up in the spam folder.

By following these tips and techniques, you can improve your email deliverability and ensure that your messages are reaching your intended audience.

Achieving strong email deliverability is crucial yet complex, requiring an eagle’s attention but the payoff is huge, engaged subscribers, more conversions, and brand reputation. As threats evolve, collaboration and watchfulness are key to helping email remain a trusted channel. At the end of the day, showing value and respect for your subscribers through relevant messaging ensures your success. Let our team handle optimising your email automation so you can focus on your business, not deliverability obstacles. With proven expertise in authentication, monitoring, and list building, we guarantee your emails reach the inbox.

FAQs

What is a good deliverability rate?

You should target at least 90% of your emails arriving in the primary inbox folder, anything below 70% risks harming engagement and the sender's reputation.

How frequently should I send emails when warming up a new IP address?

When starting with a new IP, send only a small number of emails per day, like 500-1,000. Gradually increase the volume over several weeks until you reach your target levels

What is considered an acceptable complaint rate that avoids harming the sender's reputation?

You should aim to keep complaints below 0.1% of subscribers, anything above 0.5% is dangerous and risks blacklisting. 

How can I diagnose and fix a declining email deliverability rate?

Check blacklists for IP or domain blocks, authentication issues, inactive subscribers, content triggers, and technical problems. Keep in mind to address the specific causes, don't just increase volume.

What are the benefits of implementing email authentication protocols like SPF and DKIM?

Authentication verifies your identity as a legitimate sender so more emails reliably reach inboxes instead of getting flagged as spam.