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See FeaturesEmail deliverability guide: Best practices & tips for 2024
Building an effective marketing campaign for your ecommerce business requires you to understand many things about advertising online. Emailing your customers is one way you can get their attention and encourage them to take action, such as using a coupon or signing up for a newsletter.
If you plan to launch an email marketing campaign for your online store, email deliverability is a term you should familiarize yourself with.
In this guide, we explain email deliverability and provide best practices and tips to help your business succeed in 2024.
What is email deliverability?
An email campaign uses your customers’ emails to send messages and advertisements to their inboxes. Email deliverability refers to whether your emails get delivered as intended.
If your emails reach the inbox, they have a better chance of being opened and read. However, if they end up in the spam folder or fail to be delivered altogether, your message is most likely to be missed. Factors like sender reputation, email content, and recipient engagement all influence deliverability, making it a crucial aspect of your email marketing strategy.
Why email deliverability is important
Good email deliverability is important because it means your email marketing campaign efforts are effective. You work hard to craft emails that will appeal to your audience, not to mention the hard work that goes into building an email list, so you want your emails to make it into inboxes where they can be seen.
To achieve good deliverability, your emails have to meet a number of requirements to get by the filters of the mailbox providers. Many emails get lost in a spam folder because of things like a wrong subject line or lack of user engagement.
Improving your email deliverability can help you gauge the percentage of your audience you’re actually reaching and avoid spam placement issues. You can troubleshoot any deliverability problems to learn whether your email address validity, sender reputation, email content, or something else is the cause.
What is a good email deliverability rate?
Although email deliverability is important, your actual rate is only known by mailbox providers — it isn’t something that you will see or be able to track.
Instead, email service providers use a delivery rate — this is the percentage of emails that are successfully accepted by the receiving servers. When you send your emails, your provider will show you how many were sent and how many were successfully delivered, and this is your delivery rate.
What are SPF and DKIM?
When discussing email deliverability, you’ll often hear the terms SPF and DKIM. Let’s look at each in turn to learn why they’re so important for ensuring that your emails land in your recipients’ inboxes.
SPF
SPF stands for the Sender Policy Framework, an email authentication protocol allowing the domain owner (usually the store owner) to specify which mail servers they use to send emails.
Essentially, the SPF states that any emails coming from this domain will be using these mail servers. The SPF record lists which IP addresses are authorized to send an email on behalf of the specified domain.
When sending an email, email providers will do an SPF check where they verify the SPF record. In the SPF check, they look to see if the IP address used to send the email is listed in the SPF record. If it is, then all’s fine — but if it isn’t, then the messages will fail SPF authentication, and the email will be blocked.
SPF records are vital to block spammers and phishers (the bad guys) from emailing your recipients and pretending to be you. These forged emails will more likely be blocked from reaching your subscribers’ inboxes, ending up in the spam folder instead.
In terms of email deliverability, an SPF-protected domain is less likely to be forged and, therefore, less likely to be blacklisted by spam filters. That means domains with an SPF record will be more likely to reach the recipient’s inbox.
DKIM
DKIM, or DomainKeys Identified Mail, is another authentication protocol. It can be considered a digital signature that companies use so email providers can confirm their emails are legitimately from that company and not from scammers or spammers.
This way, DKIM makes the message easier to trust (if it’s a regular company with a standard domain). However, if the company or its domain has a poor sender reputation, and is, therefore, more likely to be blacklisted, DKIM won’t help much.
Again, much like with SPF records, using DKIM means spammers/phishers are less likely to forge mail from your company. This would mean a lower chance of the domain being blacklisted and a higher chance of the emails ending up in your recipients’ primary inboxes.
What is IP warming?
IP warming is when a sender gradually increases the volume of messages sent with one IP address. It’s necessary for establishing a reputation with internet service providers.
If your sender’s reputation depends only on you, IP warming usually depends on your email service provider. Email marketing platforms cover the IP warming process because they have a lot of shared IPs for their clients and take care of them all.
Only companies with a huge sending volume that reaches 1.5 M emails per month start using their own dedicated IPs and warming them by themselves.
Building your sender’s reputation
The sender reputation is a score that mailbox providers give to senders when deciding whether to put an email in the inbox, promotional tab or spam folder.
The main goal of mailbox providers is to provide a good user experience to their users, and to only deliver mail to the inbox when they believe the reader will find value in it.
Multiple factors affect sender reputation, including:
- Authentication
- Domain reputation
- Technical configuration
- List quality
- IP reputation
- Sending volumes
- Recipient engagement
- And more
Most of these factors are only visible to the mailbox providers, so you aren’t able to see if you need to improve any of them. However, you can look at engagement signals to get an idea of how mailbox providers may see you.
Positive engagement signals
- Open and click rates
- Replies
- Categorizing: actions like moving an email from the spam folder to the inbox are a strong signal for the mailbox providers that your emails should go to the inbox
- Forwards: as with categorizing, this is a very strong signal to the mailbox provider’s algorithms
Negative engagement signals
- Marking emails as spam
- Deleting without opening
- Unsubscribing
What is a domain reputation warmup?
Domain warmup is a process of improving your overall sender reputation so that you avoid the spam folder. You do this by gradually increasing the number of emails you send out based on a specific schedule.
Domain warmup is highly recommended if you send more than 5,000 emails a day.
This procedure is typically done when:
- You’ve just moved from one email marketing service to another one
- You’ve just started with email marketing
It’s also vital that the subscribers in your first few rounds are pretty active.
This means they’ll be more likely to open your emails and click them, which signals to Gmail, Outlook, Yahoo, and other providers that your content is relevant to them and your brand can be trusted.
How should you get started with reputation warmup?
Gradually increasing your email volume helps you build a good and strong email sender’s reputation.
Warm up sending volumes and segmentation recommendations:
Campaign | Volume/Campaign | Recommendations |
Campaign 1 | 5,000 | Placed order once in the last 7 days |
Campaign 2 | 7,000 | Placed order once in the last 14 days |
Campaign 3 | 10,000 | Placed order once in the last 21 days |
Campaign 4 | 13,000 | Placed order once in the last 30 days |
Campaign 5 | 16,000 | Placed order once in the last 45 days |
It’s also a good practice to segment out those contacts that haven’t opened a campaign in the last 12 months. Learn more about that here.
And it’s best to not even import them to the new email marketing platform, at all, as they will damage your sender’s reputation on the new platform.
Here’s a sample sender’s reputation warming schedule for a client if they have 50,000 recipients in total:
Email deliverability issues
What are the factors that negatively affect email deliverability?
1. Low engagement
If a subscriber receives 50 emails but does not open any, this is just another signal to the inbox provider that the sender is not following best practices.
Therefore, more and more of their emails will be placed into the spam folder. Again, check for how the email addresses were collected.
Proactively saying “goodbye” to inactive contacts is always better than waiting for them to unsubscribe. There are some best practices on how to do it thoughtfully. Learn more about that here.
We’ve seen multiple times when a smaller active email list of 10,000 contacts drives much more sales than 50,000 (because 40,000 contacts were inactive and those bad contacts were damaging the sender’s reputation). Plus, sending emails to inactive contacts isn’t cost-effective.
2. A high complaint rate
If recipients find your email unwanted, they may mark it as spam, significantly damaging the sender’s reputation. Consequently, this can lead to all your emails ending up in the spam folder. Thus, to maintain a strong reputation, it’s essential to minimize spam complaints as much as possible.
3. A high bounce rate
This usually means that the list is outdated, low quality, or contains email addresses that were purchased. Inbox providers treat such senders poorly, which affects their reputation.
4. Too frequent campaigns
Even high-quality subscribers might be overwhelmed by receiving too many daily campaigns and will mark your emails as spam. Some will even unsubscribe from your emails.
The ideal frequency is two or three times/week. For daily senders: no more than once a day (with rare exceptions when there is a super exclusive once-in-a-quarter sale, etc.).
5. A sudden increase in the number of emails sent
If a sender usually sends to 50,000 subscribers and then starts sending to 150,000, this spike will cause more emails to be sent to the spam folder (because inbox providers consider spikes an unexpected behavior and spam attack).
If you want to increase your mailing list size, do that gradually.
6. Constantly switching between different email service providers
This hurts your sender reputation because the inbox provider might start seeing the sender as a spammer trying to hide their trail.
Improve email deliverability: Best practices
By improving your reputation profile, you will increase your success score. These are best practices for email deliverability to achieve that:
1. Send emails to a highly engaged email list with a high click rate
The “high click rate” threshold here will depend on your industry. That’s why subscriber segmentation will be your best friend.
For ecommerce that sells apparel, small electronic devices, books, or household pieces, the average click rate is 5-6%.
2. Make sure the email is wanted
This means that the subscriber explicitly agreed to receive an email. That’s why lists must be opt-in and preferably GDPR-compliant.
If you notice a high unsubscribe rate, you might want to check how the email was captured in the first place.
3. Gradually increase sending volume
As already discussed, if you have 500,000 emails in a list, starting your email marketing by immediately sending campaigns to all of them is a really bad idea.
If you start sending large batches on day one, inbox providers might see this as a threat and a spam attack. Therefore, your email will automatically be marked as spam.
4. Keep your contact list clean
Statistically, 30% of subscribers change email addresses once per year. So, you should clean and take care of your email list periodically.
If someone hasn’t interacted (clicked on your emails) in the last 12 months, that contact should be treated as inactive.
Such emails might later become spam traps. If a trap receives emails, this tells inbox providers that the sender isn’t following email marketing best practices.
As a result, your reputation suffers.
Pro tip: When migrating from one email marketing platform to another, start by transferring your most engaged contacts — those who constantly open and click your emails — and send to them only.
That way, you’ll gradually transfer your “reputation” from one email marketing platform to another.
Once you’ve established a solid foundation with this core group, you can migrate the rest of the mailing list.
Once again, migrate gradually. Start with a small list, then grow the number of contacts.
How to improve your email deliverability step-by-step
Essentially, there are a few things you can do today to make sure your deliverability and overall email delivery rate come in at a good level:
Step 1
Firstly, you should be using SPF and DKIM to ensure that mail providers can verify in one way or another that the messages are coming from you. That will help keep your email deliverability at a good minimum base level.
If you’re sending emails from your WordPress website, you can easily ensure SPF, DKIM, and DMARC are correctly configured on your domain with a plugin like WP Mail SMTP. If any of your DNS records are missing or broken, WP Mail SMTP will alert you right away so that you can fix the issue.
Step 2
After that, you need to ensure you’re sending emails only to those contacts who want to hear from you. That means proper list management is key — clean your lists regularly, every six to 12 months or so.
Step 3
Subject lines need to convince your recipient to open your email. However, some keywords in your subject line can land your emails in the spam folder, hurting your open rates and overall campaign results.
A good subject line can equal a good open rate, helping to improve your email delivery and campaign results overall. Learning the best practices for crafting solid subject lines could prevent your emails from ending up in the spam folder.
Our Email Deliverability Reports give Omnisend customers personalized recommendations on how to improve their deliverability. This includes crafting exceptional subject lines, using a custom sender domain, and changing your sender email address.
Key takeaways
Email deliverability is important and you need to follow best practices to achieve good results — and remember, it’s easy to damage your reputation if you stop adhering to them.
And even if it happens, these are the essential things on how to improve your email deliverability:
- Try testing email deliverability using one of many email deliverability tools
- Warm up your domain
- Keep your list clean
- Segment your lists to get the best engagement rate possible
- Be patient.
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