Back to blog

How We Help Marketers to Improve Email Deliverability: 6 Success Stories by Mailigen Delivery Team

Email Deliverability Visualization

Recently I have been asked a lot of questions about email deliverability, e.g. how to get more emails delivered in inbox instead of junk, why emails end up in junk, what affects email deliverability, how to improve email deliverability and a lot more.

Helping email senders, giving them guidelines and answering their questions was a positive challenge for me from which I also learned a lot. So here are my insights into improving Email Deliverability.

Only some email marketers know that Email Delivery differs from Email Deliverability. For those who didn’t know it yet, here’s the difference:

  • Delivery means how many emails are Delivered vs. Bounced
  • Deliverability means how many emails are Delivered in Inbox/Promotions tab vs. Spam/Junk folder.

Why is it so hard to deliver emails in the inbox?

In most cases, it is related to your email engagement, in other words – how your email recipients interact with your emails. Here you can read more about how your email engagement is affected when your email users interact with your emails.

During the past two years email deliverability gets more and more challenging as email services keep enhancing their anti-spam algorithms to protect our inboxes and that, of course, is a very welcome improvement, but it makes the marketer’s life a bit more difficult as well.

verifying email deliverability

What can we do to improve your email campaigns’ deliverability?

To get your emails delivered in the inbox, it’s not enough to check if your campaigns comply with anti-spam laws. If you don’t know appropriate tactics, you can easily damage your domain’s reputation, ensuring that your next email campaigns will drop mostly in the junk folder. Here are some examples:

  • You didn’t send any emails during the last six months. If you use an old email list, it may contain inactive emails (hard bounces).
  • You have a single-opt-in form on your website or subscribers have not clicked a verification link to confirm their subscription. A list with single-opt-in emails may include spam-traps.
  • You’ve included links to a third party in your email content. These links may have a bad reputation – if your email contains those, it probably will drop in the junk.

These factors may affect your reputation and future engagement, so by not following the best practice, you can influence your future email deliverability badly. There are dozens of examples. If you are stuck and you need an email delivery audit or just a consultation, contact us, and we’ll do our best to help you.

Even well-known brands face deliverability issues, when email marketing managers miss out on some know-how. It’s only human in today’s fast changing IT environment. We at Mailigen continuously improve and change our systems to be compliant with the latest standards and help our customers excel in this as well. At the same time we help new customers whose brands are affected by poor deliverability and whose emails are mostly delivered in junk instead of inbox.

One of the ways how we help is by doing Email Marketing Audits to analyze sender practices, e.g. the way how and where the sender is gathering his email list, what is his domain reputation, content deliverability, and other factors. Some of these audits take up to 20 working hours, but we at Mailigen are always willing to help.

From junk to inbox: 6 success stories

There are many reasons why emails cannot be delivered in the inbox. I would like to highlight six different situations which we turned into success stories and why it is a good idea to have professionals do the email delivery audit!

    1. A company’s emails were 100% delivered in junk because of a phone number. Interestingly, the phone number was not added in the template’s content but in HTML code – in an image ALT tag. By removing the phone number from sender’s HTML content, 100% of emails started to drop in the inbox.
    1. By using W3 tool we detected that the sender had been using a wrongly coded HTML template with errors and warnings that affected deliverability to several email services. We helped the sender improve the HTML code in his template which resulted in his emails being delivered to the inboxes while previously they landed in junk.

      Broken HTML

    1. Sender used a combination of bad engagement words in the email subject line that affected email deliverability and open rate. Note: Bad engagement words are not only spammy words like BUY NOW, 100% FREE, ACT NOW, $$. Those can also be less scandalous phrases, for example, “50% discount for good wine”, if many spammers have used this phrase previously. In other words – if more spam emails were sent containing this phrase than legitimate marketing emails, then this combination of words is affected and your emails marked as spam. We offered the sender alternatives for a better subject line, thus improving the deliverability and open rate for his email campaign.

      Evil Spam

    1. The sender used a sentence in his content which caused his emails to drop in junk in one of known email services. It is possible that this sentence structure was also used by other mailers whose subscriber engagement was low. E.g. if you include the same phrases in your email campaigns that others use (and if they have low engagement), your emails may fall in junk because of the algorithm trying to find similarities with spam. For example, this is how  Bayes spam filter system works.
    1. One long-term customer suddenly saw his email open rate drop from approximately 21% to 15%. He hadn’t made any changes to his email content or practices; there had not been any attacks against his brand and he was sending his email campaigns from a dedicated platform. We analyzed the data from our monitoring tools and detected that there had been a problem with the anti-spam algorithms in one email service. We encouraged the customer to continue following the same practices in his next campaigns, and he went back to 21% open rate. Conclusion – short-term open rate drop does not always mean that something has to be changed in your sending practice.
  1. The customer had been sending email campaigns for years, and his open rate was a meager 5%. Low open rate affected deliverability, which again affected engagement. After our audit to improve his reputation, he started to send re-subscribe campaigns periodically to those who hadn’t opened his newsletters in the past five months, using our segmentation function. This helped him to improve his deliverability step by step.

Note: The frequency of re-subscribe campaigns depends on your open rate and email services to whom you are sending emails. Your active readers segment should have an open rate of 7-15% over the past five months. For example, if your average open rate is 5% (including active and inactive readers), you should start sending emails only to those who opened your emails in the last 5 months to get an open rate of at least 7%-15%. When you’ve reached that, you should send re-subscribe campaigns to the past 5-months non-openers, but always keeping your average open rate above 7-15%. If you are working with 15% open rate, your reputation will improve faster.

P.S. It is very important to avoid spam complaints while improving your reputation.

Does Mailigen prepare Deliverability audits for those who send SPAM – unsolicited messages? The answer is NO. Why? There are many reasons why we hate spam as sure you do too. That’s why, in order to apply for an audit, your email list must contain subscribers that gave a clear permission to send them email campaigns. This means that when you’re adding an email to your list, the subscriber clearly knows what you’ll be sending him. If you are a Mailigen Customer or are considering to become one, contact us and we will help you with any deliverability issues.


Right now there are no tools available that will show you exactly how many and which email recipients got your email campaign in junk or inbox. By using inbox placement services as MailMonitor, ReturnPath Inbox Insight & SendForensics you can find out your estimated deliverability rate in top global Email Services – Gmail, Microsoft, Yahoo, AOL,, and others. Or you can use ReturnPath Inbox Monitor – this may be quite expensive, but you can get the most accurate and comprehensive data about your domain’s inbox placement.

Thank you for reading this! If you found this article useful feel free to like, share, and comment!

Author Bio

Aleksandrs Vilums is working in Email Industry for seven years. He is Mailigen’s Email Delivery and Deliverability Expert who also supervises the Delivery Team. As Delivery Team Leader and projects system analyst, he is responsible for Mailigen’s Email Delivery Systems Projects, their quality and improvements.

How We Help Marketers to Improve Email Deliverability: 6 Success Stories by Mailigen Delivery Team
Tweet about this on TwitterShare on FacebookShare on LinkedInPin on PinterestEmail this to someone


    September 29, 2017 at 12:57 pm

    Thanks for posting such a wonderful source of information. It is having lots of tips that can anyone can easily actively, while working on social media marketing. I am honestly followed each point and implement in my current task and got awesome complement from my client. Also found the interesting link which can help include more content.
    Keep the excellent post. I really enjoyed the reading.

Leave a comment

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

© 2010-2020 Mailigen. All rights reserved.