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Improve E-mail Deliverability


Menno Schreven


Trends & developments



Expert tips and tricks to get your emails into the inbox

Email deliverability is a crucial aspect of any email marketing campaign. It ensures that your emails actually reach your recipients’ inboxes and are not marked as spam. In this article, we share some expert tips and tricks to improve your email deliverability and increase the success of your email campaigns.  

Establish a strong reputation as a sender

A good sender reputation is essential to ensure that your emails end up in your recipients’ inboxes. Some factors that influence your sender reputation are:
  • The number of emails you send;
  • The percentage of emails opened and clicked on;
  • The number of spam complaints and unsubscribed recipients;
  • The quality of your email list (think segmentations rather than bulk).
Make sure you regularly check your sender reputation and take necessary measures to improve it. Analyse the above statistics to further improve your reputation.  

Use double opt-in

Using double opt-in helps you build a quality email list of interested recipients. Double opt-in requires recipients to confirm their e-mail address by clicking on a link in a confirmation e-mail. This reduces the chance of spam complaints and increases your email deliverability.  

Send relevant and personalised e-mails

Sending relevant and personalised emails ensures that your recipients open and read your emails, which in turn improves deliverability. Segment your email list based on demographics, interests and behaviour to send personalised and targeted emails. Also take into account the engagement of your database and exclude unengaged recipients where necessary.  

Optimise your email subject and preheader

A catchy and relevant e-mail subject, combined with an attractive preheader, increases the likelihood of recipients opening your e-mails. This has a positive effect on your sender reputation and email deliverability. Run A/B tests to determine the best subject lines and preheaders.  

Send e-mails on the right time

The time you send emails affects open and click rates. Test different sending times and days to determine which ones work best for your target audience. This is different for each industry and target group. So for your business, you will have to start testing what works best.  

Check your e-mail for spam triggers

Avoid using words and phrases that are considered spam. Think about writing all titles with capital letters, quantity of urls and a good balance between text and images. Use tools to check your email content for possible spam triggers and adjust your content to reduce the likelihood of spam flags. Klaviyo has written some good tips on this.  

Use authentication techniques

Implement e-mail authentication techniques such as Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM) and Domain-based Message Authentication, Reporting, and Conformance (DMARC). These techniques help email providers verify that your emails actually come from you and not a malicious third party. By properly authenticating your emails, you reduce the chances of them being marked as spam and improve your email deliverability.  

Optimise your emails for mobile devices

With the growing number of people opening emails on mobile devices, it is crucial to optimise your emails for different screen sizes and devices. Here are some tips to make your emails mobile-friendly:
  • Use responsive email templates: Responsive templates automatically adjust to the device’s screen size, making your emails look great on both desktop and mobile screens.
  • Keep your design simple: Use a minimalist design with enough white space to increase readability on smaller screens.
  • Use large and clear fonts: Choose a font size of at least 14 pixels for main text and 22 pixels for headings to improve readability on mobile devices.
  • Optimise images and file sizes: Compress images and avoid large files to reduce the loading time of your emails on mobile devices.
  • Test your emails on different devices: Use email testing tools to check how your emails look on different mobile devices and screen sizes, and adjust your design and content accordingly.

Maintain and update your email list

Regularly updating and maintaining your email list is essential for maintaining a good sender reputation and improving your email deliverability. Here are some strategies to keep your email list clean:
  • Remove inactive subscribers: Identify recipients who have not opened or clicked on emails for some time, and remove them from your list. This will help increase your open and click rates and protect your sender reputation.
  • Remove invalid e-mail addresses: Use email validation tools to detect and remove invalid and non-existent email addresses.
  • Perform regular list hygiene: Make it a habit to clean up your email list regularly, say every 3 to 6 months, to ensure the quality of your list.
  • Re-engage inactive subscribers: Try to re-engage inactive subscribers with targeted re-engagement campaigns before removing them from your list. This can help win back lost subscribers and keep your email list active and engaged.

Use a professional e-mailmarketingplatform

A professional email marketing platform, such as Klaviyo, helps you optimise email deliverability through advanced features and tools. These platforms often offer built-in authentication, segmentation, A/B testing and reporting to improve your email campaigns and reduce the likelihood of spam tags.  


Email deliverability is an important aspect of successful email marketing campaigns. By applying these expert tips and tricks, you can improve your email deliverability and ensure that your emails reach your recipients’ inboxes. Invest time and effort in optimising your email campaigns and the result will be higher engagement, higher conversions and ultimately more sales.

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