Despite all the technical advances of the last 30 years, email remains one of the most important tools in a marketer’s success kit. This is why deliverability is so important. That said, all the skilled writing, beautiful email design, and brilliant call-to-actions aren’t worth a thing if your emails aren’t reaching the target audience’s inboxes. 


    To that point, we’ve put together a comprehensive guide on how to improve email deliverability. The goal is to get you to think like an ISP – an Internet Service Provider.


    As you’ll see, the first step to doing that is to understand what ISPs deal with every day. 


    How ISPs See Email 

    Somewhere in the neighborhood of 270 billion emails are sent every single day. That’s about 33 emails for every single person on the planet. A little more than half of those emails are business-related, while the remainder is consumer emails. It’s estimated that around 50% of all daily emails are spam.


    At the behest of those of us who feel assaulted by this onslaught of unwanted communication, ISPs have evolved to manage spam very effectively. In many cases, they can ensure that these messages don’t even reach our spam folder, let along our actual inbox. To filter in this manner, they need to be absolutely ruthless in evaluating how emails are sent. 


    This is why we recommend marketers put themselves in the ISP’s shoes when they want to increase their email performance. Now, keep in mind, these ISPs know the history of your mailing list, which messages have been clicked and which haven’t, etc. If no one is clicking your emails, there’s a good chance your messages will be lost in the shuffle.  

    clicked email


    The Goal of Email Deliverability

    To many marketers, the goal of email deliverability is right there in the name: to get your emails delivered. However, if you go strictly by your deliverability rate, you might end up with some misleading numbers. After all, you don’t just want to get your emails delivered – you want to get them good placement in your target audiences’ inbox. To get help with the content you will share with your partners and customers, visit


    Nobody combs their spam email folder for “important messages” they may have missed, yet emails sent to these folders are still considered to be successful deliveries. For this reason, you need to ignore that misleading deliverability rate and instead focus on inbox placement. 

    Email Deliverability – The journey of an email

    Barriers to Email Deliverability

    The steps to delivering emails are quite simple, which leads to many marketers not taking time to appreciate the nuances of the process. In fact, a lot can go wrong from the time you build your mailing list and send your emails to when your recipients (hopefully) get the message. For instance: 


    • Hard Bounces – This is when you attempt to send an email to an invalid address. When you get a lot of hard bounces, ISPs will see it as a signal that your mailing list isn’t very clean. Best to do an email validation as soon as possible. 


    • Soft Bounces – Soft bounces occur for several reasons, including a sudden increase in email sending volume on your end or attempting to reach full email boxes. 


    • Spam Traps – This is an email account owned by an ISP for the sole purpose of evaluating and identifying spam. If you send an email to one of these addresses, it can have a significant negative impact on how ISPs see your mailing efforts.


    • Unopened Emails – Even if everything goes as planned, you can’t force your recipients to open your emails. Even with tracking pixels (small images that report when an email has been loaded), it can be hard to receive accurate information.
    • Being Marked as Spam – If a user takes the time to mark your message as spam, it will have a negative effect on how the ISP sees your messages in the future. 


    • Unsubscribes – ISPs do track when people on your mailing list unsubscribe from your list, but they generally don’t punish marketers unless this is done en masse. 


    Email deliverability - positive and negative attributes

    Understanding the Factors at Play

    As mentioned, there is a lot more going on in the email marketing game than even the most well-informed business owners might expect. This is largely due to technological advances and to the development of a general attitude that being assailed with unwanted messages is an invasion of their privacy or an assault on their well-being. This has led to a rise in companies that help businesses navigate the process more easily, such as customer data platforms like Exponea. They work together with the following players to help get emails to your customers’ inboxes.


    • The Senders – There are roughly three types of email senders: legitimate email senders, email certification providers, and spammers.


    • The Gateways – These are the ISPs and other companies that control whether or not your email gets delivered.


    • Anti-Spam Systems – Businesses configure their spam-protection systems in different ways, so there are few overarching techniques for bypassing these services. 


    • Blacklisting Organizations – These independent companies provide reports on senders they feel are using poor sending practices. All major ISPs use these reports, so ending up on one can be a death sentence for your campaigns. 


    • Recipients – This is your audience. You want to get them to read your emails, but the ISPs want to protect them from spammers. Getting to them means using the right tools, techniques, practices, and strategies. 


    How ISPs Can Hinder Your Success

    How ISPs affect email deliverability
    How ISPs affect email deliverability

    As we’ve highlighted, ISPs are “rewarded” for their ability to protect their customers from unwanted messages. In fact, many companies will highlight their various “spam protection” methods when marketing to new users. For this reason, learning to “think like an ISP” also means understanding what tools ISPs have at their disposal to hinder your campaigns, including: 


      • Sending Limits – ISPs establish sending limits for every e-mailer, which means they create an arbitrary number of emails that they feel is appropriate for you to send at any given time. After your limit is reached, all other emails you send will be soft bounced. 
      • Blocks – This is when an ISP blocks your ability to send emails completely. It usually happens after they receive too many spam complaints. It is indefinite, but usually lasts between 48 hours and one week. 
      • Email Bulking – This is when an ISP sends your messages to a junk or spam folder automatically. You can check your analytics reports if you want to know if this is happening to you. The best practice is to create a report that shows click rates and open rates by ISP and look for any synchronized drops in both. 
    • Blacklisting – As we mentioned, if an ISP or third-party company identifies you as deserving to be on the blacklist, your IP address will be blocked until you appeal with the organization that added you to the list. In many cases, a factor in your appeal will be a commitment to practicing better sending habits.


    What You Can Do to Maximize Success

    Now that you have a better idea of how ISPs view those thousands of emails you’re trying to send per day and the risks that very practice entails, let’s talk about what you can do to ensure that you’re maximizing your email marketing results.


    1. Avoid Negative IP Attributes 


    This means avoiding bad behaviors at all costs. You need to minimize bounces and spam complaints and keep your email list as clean as possible. In some cases, the use of a customer data platform will be necessary in order to ensure information is up-to-date and accurate across all of your systems and lists. Spam trap hits must be avoided at all costs, and if you find that your emails are largely unopened, you need to step up your marketing and titling game.


    1.       Cultivate Positive IP Attributes


    Some factors that can end up giving ISPs a positive impression of your IP address include being added to a contact list or address book or being forwarded to another user. For this reason, many savvy marketers integrate these actions into their campaigns. It is also beneficial to maintain a healthy open and reply rate. A healthy open rate can be thought of as 20% or more. 


    1.       Communicate Relevant Information Frequently


    The more often you send email campaigns, the stricter ISPs will be with you. To get around this, consider segmenting your mailing list whenever possible. Personalize content to different groups rather than sending broad messages to everyone. Not only will this help with ISPs, but you’ll also invariably get a better overall engagement rate. 


    1.       Cultivate Your Reputation Outside Emails


    Different ISPs and third-party providers are constantly evaluating the behavior of your IP address and categorizing you in terms of reputation. However, you also have a reputation associated with your domain. While calculated separately, they both have the power to dramatically influence your deliverability. In some cases, your domain reputation is even more important, because it can follow your brand even if you move IP addresses. 


    All Things Considered 


    As you can see, it is absolutely crucial to understand how ISPs see your company’s email efforts if you want to have success reaching your audience. That said, maintaining a satisfactory reputation and avoiding pitfalls that can hinder your progress can require a number of separate strategies and techniques, all working in concert together.


    There are many companies that can help you manage this process and maximize your email efforts. Examples include Exponea, which has won many awards for doing just that.

    Either way, there’s no reason to have to go it alone. The internet can be a challenging and fast-moving place. It’s best to have someone help you navigate it.

    By Candace Gregg

    Author’s BIO:

    Candace joined the Exponea team in April 2020 as their Head of Marketing, US. She has been a marketer for a decade for brands including MillerCoors, Jersey Mikes, AvidXchange and now Exponea.  When she’s not running campaigns, you can find her sipping exceptional coffee, reading Sci-Fi books and working on home renovation projects.

    Author’s LinkedIn –



    1. Hi Candace, this is one of the best blogs I have seen till now for email marketing and no h=one have explained it better than you! Keep on the good work love it!

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