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Getting started with Deliverability
Getting started with Deliverability

Learn what aspects may influence the delivery of your emails.

Lina avatar
Written by Lina
Updated over a week ago

It doesn't matter how great your campaigns are if no one gets to see them. You need to work on delivering your emails if you want an excellent open rate and a high conversion rate.

Several points are affecting the delivery of your emails:

Omnisend does everything to make sending your emails as simple as possible. All you need to do is 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 can switch to a custom domain or dedicated IP address, this is not always recommended or proven beneficial and is therefore restricted to the paid plans only.

There is no single answer to why your emails are not delivered, as each email provider 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 you send your emails will also change. Your new email servers are not allowed to send large numbers of emails in one go, so to ensure they get delivered to the right inboxes, sending volumes should be increased over time.

To make this change flawless, you need to go through the Warmup plan, the main goal of which is to give the ESPs some time to update their libraries and show themselves as 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 with a better score compared to those you've established with your previous ESP.

Understanding that you must go through the warmup plan on the shared or dedicated infrastructures is essential. However, if your list is small, the warmup process may become a blind alley, bringing more harm than benefit.

Customer engagement & segmentation impact on deliverability

Engaged contacts

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

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


We think you already know there is a correlation between client engagement and deliverability. Sending an email blast to your entire subscribers' list might work from time to time. But your chances of generating sales are the highest when you create personalized content dedicated to 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 that 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 address their unique needs and 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.

General rules for spam filter-friendly newsletter content

We are sure you spend a lot of time on your email design. However, there are a few aspects you need to consider while working on them. Here is a shortlist 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 clear and visible opt-out instructions. It will protect you from unreasonable spam reports that could have ended up as unsubscribe requests.

  • Establish your brand identity. Ensure you are consistent with your sender's name and pay special attention to your subject lines and preheaders.

  • Maintain a 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 vice versa.

  • Avoid spammy content. Don't use CAPS and excessive exclamation signs; avoid using sale-like words.

  • Avoid URL shorteners, as spammers and phishers usually use those to hide their identity.

Your account technical setup

From the technical side, there are a few aspects that may impact the placement of your email in 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 use the sender's email with a free ISP domain (Gmail, Yahoo, Outlook, AOL, etc.). This is because free email providers have their own authentication policies. To avoid the risk of delivery issues, use a Sender's email address with your own custom domain. Example: [email protected].

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 small volume senders (<20k subscribers), and in any condition, it will require the brand to go through the warmup process.

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

Dedicated IP

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

However, implementing a Dedicated IP address is recommended for high-volume senders only.

Monitoring and understanding the delivery of your emails rates

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

  • The open rate indicates the number of emails your customers have opened. If 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%. You are definitely on the right track if you find yourself above this number. If your open rate falls below - you need to review your strategies.

  • Unsubscribes indicate 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 permanent reasons, i.e., your customers' inboxes are 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 have reported. The 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 your metric to reveal the changes. 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.

Deliverability reports

Deliverability reports under the Reports tab is a place where you can find all of our best deliverability practices for your account. You will see different colors and labels based on your store's current setup. This page will state precisely what you should do at this specific moment to get better deliverability results.

Here you'll find stats for three main deliverability results. You will see different labels that define the status of the separate parameter.

Email list hygiene labels definition:

  • Good: when the percentage of high or medium-risk contacts is low;

  • Fair: when the percentage of medium-risk contacts is high;

  • Poor: when the percentage of high-risk contacts is high;

  • No status: when you have less than 100 contacts in your audience.

Sender domains labels definition:

  • Good: you are sending campaigns and automations from verified custom domains;

  • Fair: you are sending campaigns, automations, or both from our shared domains;

  • Poor: there are problems with SPF and DKIM record configuration for the custom domains you chose to send from, and action is needed.

Sender email address labels:

  • Good: you have at least one verified sender email address that contains a custom domain (not Gmail, Yahoo, etc.);

  • Fair: you have at least one verified sender email address, and that email address contains a public domain (Gmail, Yahoo, etc.);

  • Poor: there's no verified email address;

  • No status: there's no email address added.

Sender Warmup

Email warmup is a process that is used to build up a sender's reputation and increase the number of emails that get delivered. When planning a large-scale email campaign with a new account, it's essential to follow a warmup plan to ensure that emails get to inboxes.

The email warmup is a way to build up a good reputation for a new email account and raise the limit on how many emails you can send at once. Part of the "warmup" process is sending fewer emails from a new email account at first and then sending more and more emails each day. You can implement your warmup plan by clicking Open warmup planGet started.

If we notice your store is not ready for the Warmup, we'll give you tips on the changes that should be applied before starting the Warmup. It's crucial to switch to your domain before the warmup to ensure you'll build your brand's sender's reputation for the future.

There are a few essential things to remember:

  • You can start the warmup process only if you have about 20k subscribers in your Omnisend audience;

  • Once the Warmup process has started, you can send 1 campaign daily. You can send campaigns every day;

  • Each Omnisend store gets a unique warmup plan based on the subscribers count. The number of steps will be calculated automatically and can vary from 3 up to 25;

  • Emails from your enabled automations are not included in the daily limit count, so they will be sent as usual;

  • Segments for warmup campaigns are prepared automatically. The segments are based on subscription date (new subscribers first) for now;

  • Be aware that each campaign has to be a newly crafted email as you move on to the next step daily. This should be done to ensure your subscribers don't get the same email a few times. At the later steps of the warmup process, the subscribers will be combined, so the segments will include customers who have received your warmup emails before.

  • Once Warmup has started, you won't be able to send to All contacts or another segment under Campaigns → Recipients. The Warmup segment will be selected automatically for your campaign;

  • The daily limit is being updated at 00:00 UTC; you will see a banner about how much time is left when sending a campaign; This banner will also show the progress of your warmup process (how many warmup steps are completed);

  • In the Reports → Deliverability, you will be able to see the steps of the warmup process with the timeline, view the subscriber list for the current step, and view the report for the completed steps. If you wish to stop the Warmup → click Stop Sender Warmup at the right top corner, this can be done anytime.

It's important to remember that the warmup process is vital for maintaining a good email marketing strategy. When you have a good reputation, you get more credibility, email clients put your emails in the primary inbox, and your customers open your email more often. Read more about warmup in this guide.

Email list hygiene means regularly removing fake and unknown email addresses from the audience. It helps you cut costs for inactive contacts and improves your engagement rate. Based on the received result, you can go and clean your audience directly from the report. Read more about list cleaning here.

Sender domains will define stats for domains you set for campaigns and automations at this specific moment. You will be prompted to take the following steps based on the state of your sender's domain. The steps are defined by the labels described above.

Read more about the sender's domain and how to set it up in our Guide.

Depending on the quality label of your sender's email addresses, you'll be prompted to take the following steps. Once your sender's emails have good quality, you'll be able to review them from the report directly.

Learn more about the sender's email addresses here.

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

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