It doesn't matter how great your campaigns are when no one gets to see them. If you want to gain an excellent open rate and consequently, a high conversion rate, you need to work on the delivery of your emails.

There are several points effecting your emails delivery:

Omnisend is doing everything to make the process of your emails sending as simple as possible. All you need is to add your sender's email addresses, upload contacts, design the email, and hit send. The technical aspects, such as the sender's domain and IP address reputations, are managed and controlled on our side. Although you may switch to the custom domain or the dedicated IP address, it is not always recommended or proved to be beneficial and therefore restricted to the paid plans only.

There is no single answer to the question of why your emails are not delivered as each of the email providers' has its own set of filters and prioritizes them differently. In this article, we will explain what impact each of them has and what you should do to achieve a better result.

Your initial sending practice with Omnisend

When switching from one email marketing platform to another, the server used for sending your emails will change as well. Your new email servers are not allowed to send large numbers of emails in one go, so to make sure they get delivered to the right inboxes, sending volumes should be increased in increments over time.

To make this change flawless, you need to go through the Warm-up plan, the main goal of which is to give the ESPs some time to update their libraries and show off yourself as a good sender. If you manage to show good results from the very beginning, it will establish a great background and may even pay you off in a better scores compared to those you've established with your previous ESP.

It is essential to understand that you need to go through the warm-up plan no matter whether you are on the shared infrastructures or the dedicated ones. However, if your list is small, the warm-up process may become a blind alley, bringing more harm than benefit.

Warm-up with Omnisend

Customer engagement & segmentation impact on deliverability

Engaged contacts

Each ISP has its own criteria for measuring engagement. Some are more advanced than others, but all of them always evaluates subscriber engagement to make Inbox/Spam placement decisions. Microsoft, Gmail, and Yahoo are the industry leaders in usage of engagement metrics to establish email placement.

Subscribers who do not engage with your campaigns is the major cause of complaints, spam traps, and bounces. If you do not take action, you email may find itself in a lower position in an inbox or be banished to the spam folder immediately.

Improving deliverability with engaged contacts


We believe that you already know that there is a correlation between client engagement and deliverability. Sending an email blast to your entire subscribers list may work from time to time. But your chances of generating sales are the highest when you create personalized content dedicated for individual customer segments.

Ever heard about the Pareto principle also called the 80/20 rule? If we adjust it in this context it would say that 20% of your customers generate 80% of your sales revenue. Let’s find those 20%!

The best and easiest way to personalize your emails is through segmentation based on things like:

  • Demographic
  • Location
  • Past purchases
  • Position in the sales funnel

Your customers want personalized emails that speaks to their unique needs and address their specific pain points. While this approach takes more time than sending out a mass email, it is more effective at increasing engagement and improving deliverability.

How to Use Email Segmentation for Smarter Ecommerce

General rules for spam filter friendly newsletter content

We are sure you spend a lot of time on the design of your email. However, there are a few aspects you need to consider while working on them. Here is a short list of our recommendations:

  • Make sure your customers voluntarily subscribe to receive your marketing updates. Adjust your sign-up forms heading and consider enabling the double-opt-in option.
  • Provide your customers with a clear and visible opt-out instruction. It will protect you from unreasonable spam reports that could have ended up as unsubscribe requests.
  • Establish your brand identity. Make sure you are consistent with your sender's name and pay special attention to your subject lines and pre-headers.
  • Maintain healthy image to text ratio. Emails with a significant number of images and not many texts elevate a red flag for spam filters. The design should be crafted to supplement your message with images, not vise versa.
  • Avoid spammy content. Don't use CAPS and excessive exclamation signs, avoid using sale-like words.
  • Avoid URL shorteners as those are usually used by spammers and phishers to hide their identity.

Emails' content for a better deliverability

Your account technical set-up

From the technical side, there are a few aspects that may impact the placement of your email to the customers' inboxes, including:

  • Sender's email address
  • Sender's domain
  • IP address

Sender's email address

Subscribers might not receive your emails if you are using the sender's email with free ISP domain (Gmail, Yahoo, Outlook, AOL etc.). This is because free email providers have their authentication policies. To avoid the risk of delivery issues, use a Sender's email address with your own custom domain. Example:

Gmail DMARC Policy

Sender's domain

Although it makes sense to sign your domain with Omnisend as it is required to pass the authentication process, it may not be as beneficial to the small volume sender's (<20k subscribers), and in any condition, it will require the brand to go through the warm-up process.

However, if your sending volumes are sufficient or you experience deliverability problems, and you already followed all of the recommendations you may consider signing your domain with Omnisend.

Domain signature in Omnisend

Dedicated IP

Most of email marketing services have a range of IP addresses that are used for sending emails. These IP addresses are often shared by multiple customers, meaning that one customer’s sending behavior can affect the reputation of other senders on the same IP address.

However, implementing a Dedicated IP address is also recommended to the high volume sender's only.

Dedicated IP

Monitoring and understanding your emails delivery rates

When solving deliverability problems, it is also essential to set-up a feedback loop where each of the strategy changes is checked upon the metric your emails report. For the email marketing the most important stats are:

  • Open rate indicates the number of emails your customers have opened. In case this number is high - we can be sure a significant portion of your emails hit your customers' inboxes. The average open rate in the market is close to 20%. If you find yourself above this number, you are definitely on the right track. If your open rate falls below - you need to review your strategies.
  • Unsubscribes indicates the number of customers who choose to opt-out of your marketing by clicking on the Unsubscribe link. The average unsubscribe rate for e-commerce is 0.2%, but you should strive to reduce this number even further.
  • Bounces indicate the number of emails that were not delivered due to the permanent reasons, i.e., your customer inboxes is full or no longer exist. The average bounce rate for e-commerce is 0.3%.
  • Spam reports indicate the number of Spam complaints your customers' reported. An average rate of such reports in e-commerce is 0.03%, meaning that your emails should barely have any spam reports.

When looking into the numbers, remember that it may take a little time for the changes to be revealed in your metric. If you are testing, make sure to check it with different email providers. Something that works well for Gmail may not have the same effect for Yahoo or other providers.

And finally, if you experience any problems with the delivery of your emails or need any recommendations to feel free to reach out to our Support Team via chat line or by emailing us at

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