Improve deliverability with Email Marketing

With over 90% of businesses generating sales through Email Marketing, almost 40% of those emails are flagged as spam. Improving the inbox delivery rate by only a few percent could improve the sales and growth by a significant amount, especially with larger campaigns.

There are a number of ways to improve the deliverability of emails, from a seamless and sound setup, right the way through to the email content itself. We’ve listed the best practices, along with useful tools to help improve your campaigns.


1. Trusted platform/IP address

The IP address used to send the emails can significantly effect the deliverability of your campaigns. A new or blacklisted IP address won’t be trusted by mail platforms and default to being flagged as spam, bypassing the users inbox.

If you send less than 100,000 emails per month, it is best practice to use a bulk email service provider such as Mailchimp, ActiveCampaign or Sendinblue. The IP address used to send emails will be shared amongst other users sending emails and using their service. These service providers rely heavily on their IP addresses being trusted and excluded from blacklists. Some lesser known service providers may not hold the same level of protection against their IP reputation, allowing their customers to spam against the same IP you are sharing. It’s best to go with a well established, trustworthy service provider.

When you are sending more than 100,000 emails per month and if your data is strong, you could benefit from sending emails via your own dedicated IP address. Any new IP address will need to be ‘warmed up’, by slowly increasing the send quantity, until email platforms trust your IP. Once trust has been built, your IP will likely outperform any other shared IP addresses or email service provider in terms of deliverability.

There are a number of providers who you can purchase an IP address off. We typically use Mailgun because their API works great. A dedicated email marketing software, such as MailWizz, works amazing for scheduling campaigns and managing data

If you have a dedicated IP address setup, you can use this service, to check whether your IP is blacklisted.


2. DNS configuration (DKIM, SPF & DMARC)

It is crucial that DKIM, SPF and DMARC records are added to your DNS and setup correctly. Without these records, mail platforms won’t be able to tell whether you (the owner of the domain name) sent the email, or whether the email is from someone spoofing your email.


DKIM (Domain Keys Identified Mail)

A DKIM record is a digital authentication key. The setup is taken from your service provider (such as Mailchimp), or from your dedicated IP provider (such as Mailgun) – sometimes both, if you have both setup. The full DKIM record should be added to the DNS, exactly as instructed. The format will look similar to the below:

Name Type Content TTL TXT v=DKIM1; p=76E629F05F70


SPF (Sender Policy Framework)

An SPF record lists all the servers authorised to send emails. Here is an example of the setup:

Name Type Content TTL TXT v=spf1 mx ip4: ~all 3600


In the example above:

  • IP4: is our dedicated IP address which we’re sending emails from
  • include: contains the record for our Gmail emails and our Mailgun server
  • ~all tells receiving mail platforms to accept messages from senders that aren’t in your SPF record, but mark them as suspicious (send to spam)


Theres a brilliant article created by Google which provides in-depth detail about the configuration on SPF records, I’d recommend taking a look:


DMARC (Domain Message Authentication Reporting & Conformance)

A DMARC record essentially ties the DKIM and SPF above together and keeps you in the loop with reports which are emailed to you. You can use the example below, but remember to update the email address:

Name Type Content TTL
_dmarc TXT v=DMARC1; p=none; rua=mailto:[email protected] 6000


Content: v=DMARC1; p=none; rua=mailto:[email protected]

A specific mailbox is typically used to manage the DMARC reports, but you can also just use your email address, just make sure you setup rules and bypass the reports to a specific folder to keep things organised.


Error checking the config

It’s best practice to test your emails after the setup, is a great tool which will inform you whether the records have been setup correctly.


3. Email content

Email content also plays a really big part in deliverability and spam. The content refers to both the subject and body content of the email. There are a number of things we can look at to make improvements:



Sending as a user will always generate a much better response rate than a blanket email, spam filters like it too. You can get very targeted, including first names, and a signature to dress up the email as it would look sending from your own email account.


Avoid spammy words

Keywords such as Free, Investment, Offer and Discount are words which are often picked up by spam filters, avoid these as much as possible. It’s also best to limit exclamation marks! and CAPITAL LETTERS.


Links, images and spelling

Spam filters need to understand your intent. Avoid URL shorteners, check for broken links, and check spelling.

You’ll also want a good text to image ratio. The most common guideline is no more than 40% image coverage and a minimum of 60% text. While exceptions exist, this rule will generally keep you from any deliverability issues.



Because viruses and other malicious software can be embedded into documents, spam filters tend to be very aggressive with attachments, whether it be ZIP, DOCX or PDF. You’ll have much better success rate by removing all attachments and instead linking the user to a landing page.


Unsubscribe links

Hiding your unsubscribe link, or making the process difficult, will only result in poor deliverability. You’ll also encurrage users to hit the ‘spam’ button, which will effect your future sends.

Make the opt out link very obvious and consider adding ‘list-unsubscribe‘ to your mail headers.


4. Benchmark for open rates & click rates

If you’re wondering how your campaigns are performing, below is a rough guide for open rates and click rates on B2B, UK data:

Score Open rate Click rate
Very Poor 15% 1%
Average 20% 2%
Good 32% 4.5%
Excellent 40%+ 7%+


For more information regarding Email Marketing and anti-spam techniques, get in touch.

Written by

Adam Yates

Managing Director

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