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9 Secret Content Strategies To Improve Email Deliverability

July 10, 2022
9 secret content strategies to improve email deliverability

Did you know that you can increase email deliverability with a few tweaks? Unfortunately, the email inbox is a delicate destination, where only the most robust emails arrive and survive. With average email open rates hovering between 17- 20%, improving email delivery and user engagement are some of the biggest challenges email marketers face. Well, if no one opens your emails, what’s the purpose of sending them? And, if your promotional emails land in spam or disappear into the mysterious black hole?

In fact, according to a study by Digital Guardian, 91% of cyber attacks begin with a phishing email. Apart from that, globally, 6.4 billion fake emails (sent from fake From addresses) are sent every day, according to the Email Fraud Landscape Report. So if marketers know about the power of email as a medium, so do fraudsters

Email inbox placement and email delivery are getting more complex. Mailbox providers consider many factors for placing an email in the inbox. Watch the video to learn the email deliverability best practices to improve email domain reputation.

Here are some of the factors that affect email deliverability services.

  •  When email authentication is void

Firstly, when major MBPs (Mailbox Providers) look into an email, they trace the origin of the email. Secondly, they will look into email domain reputation and finally, they will ensure mails have not been altered in transit. Therefore, proper domain configurations (DKIM, SPF, DMARC, FBL, PTR, RDNS) must be in place before sending out campaigns.

  • When sending IP flagged by major blacklisting agencies

Email sender reputation is a combination of IP and email domain reputation. If IP loses its reputation, it can affect delivery drastically. However, we have seen a fall in the open rate. For example, IP reputation is bad in GPT (Google Postmaster Tool). On the other hand, it occurs when IP gets listed by major blacklisting agencies like (Spamhaus, Proof point, Barracuda, Spamcop, etc.).

  • When email domain reputation gets affected

Domain reputation plays a vital role in inbox placement as it attributes to the reputation score that the MBPs assign. Therefore, major MBP like Gmail strictly looks into the domain reputation of the sender and decides where to place the emails.

  • When engagement metrics fall

MBPs rate the sender’s reputation based on the engagement of the email sent to customers. As a result, good email engagement is directly proportional to the sender’s reputation.

  • Poor maintenance of list hygiene

Maintaining list hygiene is pivotal to keeping IP/ email domain reputation and engagement metrics intact. However, failure to maintain the highest level of list hygiene would eventually lead to compromises in inbox placement with bigger MBPs. Therefore, be aware of old inactive email list data. Some email ids can have turned into spam traps (honey pots) emails. Sending emails to traps would lead to significant email deliverability issues and a total show stopper.

  • Poor content management

Innovative email content management strategies and tricks are vital to creating good email content that, in turn, improves email deliverability. Even though you may be an expert in email marketing, you may know industry-best email marketing practices. However, it’s still not necessary that you get good inbox placement. Therefore, email marketers should smartly manage email content and deploy the necessary testing strategies to choose the best-performing content. 

Here are a few content tips for email marketers to improve their email deliverability rate and inbox placement.

1. Subject line matters

Nearly every inbox is bombarded with hundreds of emails. Industry statistics indicate that anywhere between 45 to 50% of emails a person receives are spam. Hence, If you need proof- you only need to open your mailbox and spam folder and do a random check. 

With so many spam emails, it’s not surprising that email users face the needle-in-a-haystack situation every time they open their inbox. How do they decide if a particular email in their inbox is relevant or not? How do they choose to delete, open or mark as spam?

Users look at subject lines even to identify an email as relevant or irrelevant. Moreover, we know from experience that it’s common for recipients to look at email subject lines and, upon finding them irrelevant, delete the emails or mark them as spam? 

1.1. Do not Mislead

A subject line should align with the message conveyed in the mail. Also, it should not mislead the user by making false claims or promises. However, suppose the subject line doesn’t look relevant to email recipients. In that case, it’s possible that they report the email as spam, not open it or press the trash button! 

1.2 Keep it Crisp

Stick to the prescribed number of characters in the subject line rather than trying to include everything. That is, from the brand name to offers and the rate tag. It’s better to keep the subject line below the recommended 40 characters and avoid using multiple special characters. Besides, there is a high chance for ISP filters to sieve your message and mark it as “This message seems dangerous.”

1.3 Say Goodbye to the Sales Line

It’s better to go easy on promotional trigger words like the offer, discount, free, hurry etc. After removing sale tags from the subject line, we have seen mails move to the primary folder in ISPs like Gmail. So, there is a greater possibility of mails landing in the promotional tab if an overdose of promotional words is used in the subject line. 

As many overtly promotional email subject lines come with an embarrassing barrage of numbers and symbols along with promotional terms, users may dismiss your emails as spam even before they open them. 

Below is a campaign performance analysis for one of our clients were promotional and non-promotional subject lines were used to target the same user base. Using non-promotional subject lines helps improve email inbox placement and increases the probability of the email landing in the primary mailbox tab.

The primary lesson here is – don’t look like a spammer! Steer clear of spammy words and phrases like “Jackpot”, “50% off”, “WINNER!”, “$$$ Affordable” or “100% Free”. Unless necessary, stay away from special characters ($%#), and always double-check your copy for the correctness of spelling and grammar.

2. Reply-to address (Don’t use no-reply)

It’s observed that users prefer to reply to the email address from which the mail was sent. Therefore, more replies indicate better email engagement, leading to better email deliverability. Using the “no-reply” address is considered bad practice as users are not encouraged to respond. But, Gmail’s updated sender guidelines recommend using separate reply addresses according to the mail streams (i.e.,,, etc.

From address needs to be classified based on the communication intent:

 Billing messages:

Order updates:

Notification messages:

3. Sender authenticity is important

Sender name is an essential factor influencing email recipients – from opening, deleting or marking an email as spam. However, email users look at the sender’s name and make assumptions regarding the sender’s authenticity. The sender names can make or break the email campaign performance matrix.  

There is a misconception that spoofing a sender’s name could help increase the open rate and get better engagement. Therefore, this might help to get a higher available rate. But there is a greater probability that the user will mark the email as spam when they realise they have been misled. 

Adding the brand name in the “From” field is recommended. Moreover, it helps users recognise the brand. Spammers with low or poor email sending reputations and who use purchase/ un-confirmed opt-in lists deploy these fraudulent mailing practices.

4. Personalise the content

Pause for a moment and take stock of how many emails you receive daily. 50? 100? Or, more? Personalising emails would help you stand out and obtain good results when you receive showers of emails every day. Moreover, personalising content is an intelligent strategy to strengthen ISP-wise reputation and create more value for the marketer. 

If marketers can deliver what the user expects, it’d eventually create more engagement with the mailer content. In addition, email personalisation makes your email stand out from regular promotional content, and ISPs would treat it as personal communication. All these would help your emails bypass mail filters of ISPs like Gmail. This helps gain more email engagement and goes a long way in building strong ISP relations. 

5. Avoid shortened URLs

Shortening helps to reduce the length of URLs, but unfortunately, they are also used by spammers for masking the links. URL shortening is one of the tools used by spammers to hide their malicious websites and domain from ISPs. When users click the shortened URL, it may take them to a fraudulent page which may contain malware.

You know that the URLs you are linking to are legitimate but beware – the extensive, global abuse of URL shorteners to send out spam has made them red flags for many ISPs. As a safeguard, add hyperlinks on keywords in copy or on images. Avoid using full URL links as text in the body of your email. Long URLs are not only ugly, but they can also get your emails to be flagged as spam.

6. Host images on reliable websites

It’s a common practice for email marketers to use hosting services to host images and big files and link them to email. While it helps to decrease the message size and increase sending speed and loading time, ensure the image and link hosting service providers you choose are reliable and trustworthy.

Many websites provide free hosting services that may lead to a potential blacklist. For example, the image hosting domain has a reputation and should be safeguarded as the sending domain. Major ISPs like Gmail give fair importance to the image hosting path and the domain used in the link. The bad reputation of the image hosting path can lead to spam folder placement. 

Blacklisted image hosting domains can ruin inbox placements in B2B mailboxes. This is because most organisations have internet security systems that primarily rely on blacklisting agencies. So blacklisting domains can hamper the inbox placements in B2B mailboxes. 

7. Add alt text in images

Alt text (Alternative text) is a short description of an image that will be displayed. In this way, if the image gets blocked, the user will be able to know what the image is. This usually happens to users who have blocked downloading images for a particular email client.

8. Maintain text-to-image ratio

Maintaining a text-to-image ratio is a good practice for better user engagement. Emails that are purely image-based stand no chance with users who have turned off the image-download option in their email settings. Knowing the audience and their preferences are key before deciding whether to use an image or text-based mailer.

There are situations where an image mailer performs better than a text mailer. Sometimes, we recommend marketers use image mailers to re-engage inactive users. Maintaining a minimum of 60 to 40 text-to-image ratio in email campaigns is recommended. There is a higher chance of heavy image-based emails landing in the spam folder. 

9. A/B testing

Email A/B testing determines email effectiveness regarding the open and clicks rate of two or more email creatives. In the test, two or more campaign variations are sent to a small percentage of the total subscribers. Half the recipients will be targeted with Version A and the rest with Version B. The winning version is determined by the higher open or click rates, and it will be used to target the rest of the users. A/B testing for email can be conducted based on variations in-subject line, email content, length of the mail, etc. Below is an example of an A/B test on email content.


Rome was not built in a day. The same goes for email delivery service and email inbox placement. Successful email marketers advocate time-tested strategies and email deliverability best practices for reasonable email inbox placement rates. Constant monitoring of user engagement and activity helps marketers gain insights into user needs and tailor content and communication accordingly.

As this article elaborates, email content management holds a significant role in improving email deliverability. Follow the above email content management tips and use the trusted email deliverability tools to fine-tune your content for the tremendous success of your email campaigns. As ISPs strengthen their email filtering algorithms, it’s up to marketers to stay on top of their email game – to fulfil the promises made to subscribers when they signed up! 

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