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An Insight Into the Factors That Affect Email Sender Reputation and Ways to Improve It

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Any email marketer worth their salt would have invariably typed-in this query at some point in their journey: “factors affecting email deliverability”. What next? They would have been invariably met, frequently, with the term email sender reputation. 

You might have pumped in dollars and deployed the best creative minds to craft, write and design the best-in-class email marketing campaigns, but all that effort will amount to nothing if those emails never reach their intended audience! Sounds scary? Well, cease to fret as we unravel the basics of email sender reputation, the factors that have a role to play in determining it, and finally, ways to enhance it. 

Let’s hit the throttle!

Decoding Email Sender Reputation

Your Internet Service Provider (ISP) renders a score to your organization on the basis of varied factors such as bounce rates, the success or failure of previous email campaigns, reader engagement, the number of times your email subscribers mark your email as spam, etc. 

A major determinant of your email deliverability rates, your email sender reputation could very well be the difference between your campaigns translating into visible monetary ROIs or, worse, getting marked as spam or even blocklisted! 

While building your email sender reputation is not child’s play and cannot be done overnight, it will require a concerted effort from your team over a period of time. ISPs are not very transparent when it comes to the parameters they consider before segregating those IP addresses that make the cut and those that don’t.

However, Google has rolled out an insight into its Postmaster Tools that one can peruse to gain a clearer picture. They have changed the way they calculate their spam rates; you can check the same here

A conflation of IP reputation and domain reputation, email sender reputation is influenced by both. Let’s delve into each of these elements,

  • IP reputation: While every ESP offers a whole plethora of shared IP addresses, there is also an option to purchase dedicated IP addresses. The latter is an expensive option; therefore many prefer to go with the former.

However, every shared IP comes with its own history and reputation, which servers take very seriously. A decent reputation takes years to build, and one failed email campaign to dig its own grave. Thus if you are facing a spike in failed deliveries, you know where to check!

  • Domain reputation: Domain reputation has a significant role in influencing your sender reputation. You might invest in the best, tried, and tested IP address from premia mailbox providers or ESPs. However, all of that will amount to nothing if your domain reputation is not such a hit with the network. Similarly, a well-reputed domain name won’t rake in the moolah if your IP address has a not-so-great reputation. 

Metrics Affecting Email Sender Reputation 

Just like there are a number of intertwined factors behind a person’s reputation, your email sender’s reputation is not much different. Let’s unravel some of the factors at play here;

  • Spam traps: These are anti-spam measures adopted by ISPs in order to identify and block email marketers who choose not to adhere to email distribution rules and regulations, such as buying email lists and sending out mailers to those who didn’t sign up for it in the first place. While there is no way to tell a spam trap mail id from a legitimate one, you can try looking out for those with typos and refrain from sending emails to those who don’t particularly wish to receive them, and clean your subscriber list frequently. 
  • Spam complaints: The more the number of people hitting ‘Report as Spam’ on your deliverables, the further south your email sender reputation dips. 
  • Sending history: A certain karmic connection of sorts, this involves your past sending behavior in terms of cadence and content. Spam filters are always on the lookout for those with unreasonably high sending volumes.
  • Content quality of your emails: Sending out spammy emails that aren’t grammatically correct or contain images that are too large, and content that’s obnoxiously irrelevant, you run the risk of getting marked as spam by ISPs.
  • Bounce rates: This refers to the number of emails that don’t make it to the intended inbox. They can be either soft or hard, depending on whether the bounce was either due to temporary issues, such as storage problems, or a more permanent one, such as a non-existent email id or one that is no longer in use.
  • Subscriber engagement: This is a reflection of how subscribers choose to interact with the emails you send. Open rates, click-throughs, and reply frequencies, if any, affect your reputation as a sender. 
  • Unsubscribe rates: As the name suggests, this is the number of subscribers who choose to bow out of your mailer lists. 

Ways to Salvage Sender’s Reputation

There are tools available across platforms with which you can get an insight into your current scores on the reputational front. For instance, Google Postmaster Tools can help you gain a better understanding of how well you are doing in terms of spam reports, authentication, encryption, and delivery errors. However, in order to avail of it, you need to have a high sending volume. 

Once you are clear on your current standing and seek to improve your sender reputation, the following pointers will help you; just remember to implement them in your next email campaign, or you can choose to let experts do the job for you! 

  • Ensure that your domain is authenticated: Having proper authentication protocols in place lets incoming servers know that you are indeed who you profess to be! We suggest checking the following credentials in case you are facing deliverability issues~ DMARC (Domain-based Message Authentication, Reporting & Conformance), SPF (Sender Policy Framework), and DKIM (DomainKeys Identified Mail). 
  • Choose to grow your email subscriber list organically: Playing jazz tunes to someone who likes the blues won’t really turn out that well for both parties, right? They’d either tell you to stop playing or, worse, choose to leave the avenue. Similarly, buying email lists or sending emails to those who never really expressed any interest in receiving content from you is not GDPR compliant and will have negative repercussions on your sender reputation. The way out of this is to go for double opt-ins. 
  • Regularly clean your email lists: So you have chosen to go the organic way both in letter and in spirit, congratulations! A little grooming every now and then never hurt anyone. People switch email accounts when they change jobs, and unsubscribing from your emailing list may be the last thing on their minds. Also, sometimes people run out of storage in their inboxes. All these factors can impact your bounce rates. The first is an instance of a hard bounce. In short, there ain’t much you can do about it other than getting it off your mailer list. While the second one is an example of a soft bounce, one which may get rectified over time. You can probably try shooting them emails at a later stage. In case they have lost interest over time, you could try sending re-engagement emails. And if it all comes to nothing, bidding adieu to them is a smart move! 
  • Don’t forget to add that unsubscribe button!: This may seem counter-intuitive, but in actuality, it makes a lot of sense. Letting people know that you value their time and yours helps build a clean and solid email reputation.


Well, that’s a wrap, folks! Here’s to an ever-improving email sender reputation, and in case you need help crafting those awe-inspiring email campaigns, we at Email Uplers are here to help! 

About the author


Kevin George

Kevin George is the head of marketing at Email Uplers, one of the fastest-growing email designand coding companies, and specializes in crafting professional email templates, PSD to HTML email conversion and free responsive HTML email templates in addition to providing email automation, campaign management, and data integration & migration services. He loves gadgets, bikes, jazz and eats and breathes email marketing. He enjoys sharing his insights and thoughts on email marketing best practices on his blog.