Email Testing and Rendering 101

We said it once and we will say it again. Email marketing is one of the most successful forms of marketing there is. Not only because of its high ROI, but “email is the marketing channel most consumers say they want businesses to use to communicate with them.” (Forbes) That said, you can create beautiful designs, thoughtful messages and have a near-perfect campaign but all of your efforts could go to waste if you do not test and render your emails.

What is Email Testing?

To avoid small mistakes, or larger undetectable issues it is crucial to test your emails. Email testing is a way of ensuring that your emails are displayed properly, that your designs are whole, your subject lines are error-free and your links are working. Email testing is essentially a preview of your message that can aid in pointing out a range of issues.

Deciding to test your emails is one step down the right path. You solved the issues that became visible through your test and eased concerns of broken images and peculiar fonts. However, another issue might still persist.

Email Rendering

Unfortunately, while some emails might look flawless for one subscriber, the same emails might be nothing but flawed for another. Every email has a whopping 15,000 different rendering previews. This makes it incredibly vital to test email previews.

What is Email Rendering?

Email rendering refers to the multiple ways that an email might be displayed across different clients and devices. By testing different previews, you ensure that your message will be displayed according to the various mail clients, screen sizes, operating systems and email service providers that a subscriber might be using.

How to Test and Render Your Emails

To be certain that your subscribers are receiving emails with everything from your intended design to the correct formatting, email testing is crucial. How do you go about email testing?

  • Send your emails through an email service provider (ESP)
  • Use an email testing service – the following platforms offer email testing technologies. Along with basic testing, a few of these services also test your email campaign’s possible spam score.
  • Send your emails to different devices – this will give you a feel for the different displays your subscribers will see.

When it comes to email rendering, there are several best practices that you can adopt.

  • The size of your emails – by making sure your emails are around 600px wide and below 102kb, you would be ensuring faster loading speeds and better delivery.
  • Email backgrounds – to prepare for the possibility that your background image will not render, include a background color behind the image.
  • Fonts – when it comes to font rendering, make sure to set fallback fonts to your emails. If you don’t, you risk having your messages show up in Times New Roman.


Email Development and Design

“on the development and design side, knowing what devices my audience is using to interact with the emails I build is crucial.” – Alice Li

If you are interested in topics related to email development and design, our interview with Alice Li touches upon the importance of email marketing from a development and design perspective.