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Email clients (like Gmail, Apple Mail, or Outlook), operating systems, and devices change frequently. Because there are potentially more than 300,000 different ways an email could render, email QA testing is really the only way to verify how your email will look when it arrives in your subscriber’s inbox.

But sorting reviewing how every single email displays in multiple email clients and devices is time-consuming. There’s a better way.

We compiled this list of email testing and monitoring best practices from our team of Litmus email experts to help you find new ways to test smarter, get flawless emails out the door faster, and make sure they stay flawless, too!

1. Know which email clients matter for your audience

Our Litmus customer support team is often asked about the most popular email clients, and you can find that information updated each month on our email client market share page.

While knowing the most popular email clients can help you keep a pulse on trends, smarter testing starts by knowing which email clients your unique subscribers are most likely to use.

Litmus Email Analytics can help you determine exactly what those are, so you know which email clients to focus your attention on when you’re building emails.

With that insight, you don’t have to waste time trying to make a preview look perfect in Outlook 2010, for example, if you don’t have users opening in it. Be sure to adjust your default email client list to reflect what your subscribers use.

2. Organize your email client testing lists

With Litmus Email Testing Profiles (available on Plus and Enterprise plans), you can create custom lists of email clients and devices that are relevant to your business and workflow–and label them in a way that makes sense to your team.

Whether you want to place some email clients in a “troublemaker” list, or create another for “Dark Mode,” you can toggle between preset lists of email clients and devices to easily debug your message while you build–-all the way up to your final pre-send test.

If you make last minute edits and need to run another quick test before you hit “send,” Email Testing Profiles make it easy to identify which to run. And, you can easily create, edit, and delete lists if your business needs change.

Keep in mind that the email client defaults you set for yourself do not apply to other users who may be on your Litmus account, and that each Litmus user has their own unique Litmus test address to send in tests.

Litmus Email Testing Profiles

3. Know you’re testing for the latest devices

Apple released the iPhone 15 and iOS 17 in September 2023, and sold 235 million units. It’s smart to know what subscribers who’ve updated their devices or OS version will experience on them. To provide that insight, Litmus’ email client support has expanded to include the latest devices:

• iPhone 15 (iOS17)
• iPhone 15 Dark (iOS17)
• iPhone 15 Plus (iOS17)
• iPhone 15 Plus Dark (iOS17)

Need to test how the newest iOS would render on an older iPhone device in previews? You can refer to the resolution size of devices to understand the rendering. For example, the iPhone 14 shares the same resolution as the iPhone 13 and 12. That means you can look to the newest email client previews for iPhone 14 (iOS16), to see how the iPhone 13 and 12 would also render on iOS 16.

4. Preview email from the subscriber’s point of view

Email service providers (ESPs) can change your email code upon sending, which could affect rendering. Because your subscribers will be receiving the email sent from your ESP, send a test  from your ESP to Litmus. That way, you’re sure to see what they’ll see–and can catch any issues caused by the ESP.

(Sending in your test also ensures you get abbreviated Spam Test results at the bottom of your Litmus Previews & QA tab).

Pro Tip: You can better manage your preview usage in Litmus Builder by adjusting your default email client list and waiting to check the previews until you’re close to done. If there are problematic previews, select only those (or add them to the “troublemaker” list we mentioned above) so you’re only focusing on running the previews you need.

(Got an email client preview requests? Email hello@litmus.com to share your requests. Our engineering and product teams love to hear what people want next!)

5. Ensure your emails are conducive to subscriber action

The most perfect email in the world may get lost in the shuffle if subscribers can’t access it quickly.

If the loading speed for an email is longer than one second, Litmus email designer Hannah Tiner makes sure to investigate if the email needs further compressing—since longer load times can be expected for long or image-heavy emails.

A Litmus Test shows you how many images are in your email, the size of each image, and the total size of all of the images.

Tiner also recommends checking:

• • Margin/spacing issues
  • Correct image sizes
  • How colors render on Dark Mode
  • Font fallbacks displaying correctly
  • Broken images
  • Content stacking on mobile
  • Color contrast being strong enough
  • CTAs and buttons rendering as intended so readers take action
  • Blue hyperlinks where they shouldn’t be

6. Don’t skip the spam test

The days of avoiding certain phrases to avoid the spam filter are over. The nuances of email deliverability and factors that determine if your emails make it to the inbox is far more complicated than avoiding a phrase.

Follow best practices for authentication and engagement to avoid being marked as spam–and always carve out time for Spam Testing, so you can spot any issues that would impact your send—or prevent your message from reaching your audience.

7. Use integrations to your advantage

When you can preview, test, and troubleshoot your emails without the need to switch back and forth between tools, you can simplify testing even further and streamline your production process. Litmus ESP integrations and the Litmus Extension make it easy to test emails—including some ESPs that support  dynamic content—with a single click.

8. Scan for problems

You don’t have to wonder if your email looks great when you send it today, but what if it changes tomorrow because an image stopped appearing or a link broke? Litmus Email Guardian watches over your emails and notifies you of any significant changes so you can fix them before your next send.

Email Guardian monitors your email for unexpected changes caused by updates from webmail clients like Gmail, Yahoo Mail, Outlook, and Outlook 365 Desktop or other external factors.

Email Guardian also monitors your link functionality, letting you view your link journeys, preview your link destinations, and be the first to know if your email contains a broken or slow-loading URL. Monitor as many emails as you like.

What about images?

Email Guardian’s next trick is email image monitoring, a powerful feature that helps keep watch over your email images and alert you if an image is broken or slow-loading.

Images are a valuable element to your email design, so ensuring your emails contain high quality images that don’t negatively impact your email sends is vital. Image monitoring in Email Guardian helps you identify, find and fix email images that need your attention before you send.

Watch the video below to learn more about email image monitoring in Email Guardian.

 

 

Thanks to these features, you can rest assured that your emails are heading out in style and landing in your subscribers’ inbox. Let Litmus Email Guardian help you keep your subscribers’ experience exactly the way you intended.