How to Improve Email Deliverability?

improve cold email deliverability

The tactical objective of your cold email campaign is to land your emails into your Prospect’s Primary Inbox, where they will be read and not in the Social, Promotional, or Spam folders.

Why is cold email deliverability important?

The number of spam and phishing emails is increasing daily, so email providers are being more careful about what gets into your inbox.

They’ve started using brilliant filters to catch these bad emails. Cold Email deliverability is all about dodging these filters and reaching your prospect’s primary inbox. 

After creating an email account, you enjoy good cold email deliverability when you send emails within your organization or to clients. It becomes an issue when a cold email campaign is launched with the same account. The emailing behaviours have changed, and the number of emails going out has drastically increased. Such behaviour triggers the spam filter. 

All follow-ups emails will land there if your initial email goes to the primary inbox. 

Emails in the spam folder are less likely to be opened and read. Common sense, no?

By ensuring good email deliverability, you increase the chances of recipients engaging with your cold emails. This leads to more responses, which eventually turn into sales. 

Note: Never start a cold email campaign with your primary email domain. If you have one started, then please stop it immediately. Set up a secondary domain for cold emailing.

What are the factors affecting your cold email deliverability?

When you hit send, Email Service Providers (ESPs) check a bunch of stuff before your email lands in your prospect’s inbox.

Here are the factors that affect your cold email deliverability –

  • Sender Reputation: This is like your email reputation score. If prospects open and engage with your cold email, your email senders reputation improves. But if your emails often get marked as spam or ignored, your reputation suffers. 
  • Abuse Reports/Spam Complaints: If recipients report your emails as spam or mark them as abusive, it raises a red flag. Email providers take these reports seriously. 
  • Sending Volume: Email providers want to prevent spammers from flooding inboxes, so they monitor sending volume closely. If you usually send 15 emails a day and suddenly send 300, it might look suspicious to email providers.
  • Blacklists: Email providers maintain lists of known spammers’ IP addresses. If your sending IP is on one of these blacklists, your emails will likely be marked as spam. 
  • Text-to-Image Ratio: Emails with too many images and very little text can resemble spam. Spam filters might flag such emails.
  • Number of Links: Excessive links in an email, especially if they lead to suspicious websites, can trigger spam filters 
  • Text-to-HTML Ratio: Emails that are too heavily formatted with HTML and lack plain text can be flagged as spam. If your cold email is mostly fancy graphics and design, it might be seen as spam. 
  • Spam Triggering Words: Certain words and phrases in your email content can trigger spam filters if used excessively. Words such as scams, promotions, or explicit content. Using phrases like “Act Now,” “Guaranteed,” “Limited Time Offer,” or “Winning Lottery” frequently in your email content can also trigger spam filters.
  • Unverified Email List: Sending emails to unverified or purchased email lists can significantly impact your email deliverability. As these lists may contain outdated or invalid email addresses, increasing the likelihood of bounces and spam complaints. 

All these technical factors work together. You can’t just fix one and ignore the rest. They rely on each other to ensure your emails are safe and get to where they should be. So, paying attention to these technical details is crucial for successful email delivery.

How to ensure cold email deliverability?

Here are some guidelines to improve your cold email deliverability; let’s see them one by one.

#1 Focus on your email sending volume

Email Service Providers (ESPs) have certain thresholds for daily sending limits; if you exceed those, you will get a temporary suspension showing an error – “sending limit exceeded“. This is the first thing you want to look out for.

Businesses that aim for high cold email deliverability rates keep their daily email sending limits under 50 emails per day per email address.

#2 Personalise your emails

If you are personalizing emails (which you should be doing), each email will appear different to ESPs, and this helps in deliverability.

#3 Try “Inbox rotation”

Inbox rotation can greatly improve email deliverability. Inbox rotation is a technique in cold emailing where you send emails from multiple email accounts to avoid spam filters and maintain a good sender reputation.

Inbox rotation by

By distributing your campaign across various email inboxes, you reduce the number of emails sent from any single address, which appears less suspicious to spam filters.

Additionally, it prevents anyone inbox from being flagged for exceeding daily sending limits while also allowing you to bypass those limits set by email providers altogether. SmartReach provides adding unlimited sending email accounts to your cold email outreach campaigns.

#4 Implement ESP matching for your cold email campaigns

ESP matching helps with email deliverability in cold outreach campaigns by making your emails appear more natural and bypassing spam filters.

When you send emails through the same email service (e.g., Gmail, Outlook, Apple Mail) the recipient uses, it looks like a regular exchange, increasing trust with email providers of the recipients. Additionally, ESP matching avoids triggering spam filters by distributing your emails across various providers, disrupting patterns that might flag them as bulk or unsolicited.

#5 Run email warm-up for all your email accounts

Email warmup help you build trust with email service providers and build your sending reputation. Whether you’re using a new email address or you’ve had a tough time with emails going to spam before or constantly cold emailing, doing the warmup right is a must.

For a recently registered domain, you need to ramp up your email sending gradually. You could start with 3 – 5 emails on day one. Then, slowly, over a period of days, take up to 40 to 50 emails daily.

This process is tedious to manage manually.

SmartReach allows you to gradually warm up your email campaign to maximum volume over several days.

Try and keep your sending email always connected to a warmup tool or always have a backup email warmed up at all times.

You’ll find many email warm-up tools out there. Don’t blindly go with the cheapest, as they could do more harm than good. SmartReach provides free email warm-up tool “WarmupHero” for automated email warm-up process.

#6 Use “Spintax” to create email variants

Spintax is a method used to make every email different. It creates multiple variations of a single email message by substituting words or phrases with alternative phrases or variations.

If you send the exact same email to a large list of recipients, it can trigger spam filters. Spintax helps you generate slightly different versions of your email, reducing the chances of being marked as spam. Here is an example

Original introduction:

{%spin%}Hi|Hello{%endspin%} {{First_Name}},

Original value proposition:

{%spin%}I noticed you|We noticed{%endspin%} are interested in {{Subject}}. {%spin%}Our solution|Our product{%endspin%} can help you {{benefit}}.

Possible variations:
Hi John, I noticed you are interested in Marketing. Our solution can help you increase your brand visibility.
Hi Jane, We noticed you are interested in Sales. Our product can help you increase your top line.

Original CTA:
{% spin %}Let’s schedule a call to discuss further|Get in touch if you have any questions|Reply to this email with your availability {% endspin %}.

Possible variations:
Let’s schedule a call to discuss further
– Get in touch if you have any questions
– Reply to this email with your availability

#7 Set-up your email authentication records properly (DKIM, DMARC, SPF)

➡️ DKIM is a protocol that lets your recipient know that this email came from someone in your domain authorized to send emails. Setting up DKIM requires you to set up a DNS record. View this article to learn how to set-up SPF, DKIM and DMARC for Google workspace.

➡️ SPF or Sender Policy Framework is a record that publishes which IPs are allowed to send emails on behalf of a particular domain. This is a DNS Record that has to be published for your domain.  View our help page to understand how to set this up. 

➡️ DMARC is a  3rd type of DNS record that has to be published for your domain. It ties the SPF and DKIM records and helps the receiving email server decide what to do with the email that arrives, which fails the SPF or the DKIM check.

#8 Provide an opt-out option for your recipients

You have no control over whether your recipient marks your email as spam. But if you give them an option like an unsubscribe link , instead of marking your email as spam, they can opt out of emails from you.

This is far better than getting your email marked as spam and lowering your email’s reputation. Hence, always include an unsubscribe link in your email.

Some spam filters scan your email body for the word “Unsubscribe”. provides an option to hyperlink your unsubscribe link to text. So you can use “Not now,” “Not Interested,” “Stop Sending” or anything customozed with a link to unsubscribe.

#9 Verify your email list twice before you hit the “send” button

If you purchased an email address list from somewhere, it may contain email addresses that are no longer valid (the person changed companies) and some emails that are repurposed for Spam Traps.

Email verification tools can purify your list and give you a cleaner list by identifying invalid emails in the list. This improves your email bounce rate and hence enhances your deliverability. SmartReach automatically verifies every email address before sending the email to a recipient for free.

In summary, you want to monitor your spam rate, sending volume, and first-time sending for a new domain. Additionally, you want to personalize your emails, verify your email address list, and ensure you have an unsubscribe link.

Finally, you want to be sure you have done your technical setup correctly for your domain – DKIM, SPF, and DMARC DNS records.

SmartReach provides you with reports on emails marked as spam and bounce rates. It also has features to personalize email via Spintax and merge tags from your uploaded data.

SmartReach can be set to ramp up your sending volume gradually for newly registered domains and will automatically verify and clean your mailing list before sending emails to them. Finally, our support articles on DKIM, SPF and DMARC setup should have you moving on this front.

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