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Email Testing Uncovered ☑️ : Tips, Benefits, and Tools

Rida Ali Khan

What do you think is an email marketer's biggest nightmare?

Emails landing in the spam folder, HTML code breakage, incorrect links, or designs lacking accessibility?

Well, actually, all of the above and literally anything else that hinders email’s performance.

And to avoid making these nightmares a living reality, you must run rigorous email testing before sending emails out. And when we say testing, we mean testing them out like you are your toughest critic.

Want to become a pro at doing so? Then, keep reading this article, as we’ll share the best practices, tips, and expert advice on testing emails to make them flawless and worthy of high engagement.

But before jumping into technicalities, let’s discuss why email testing is important.

Why Does Email Testing Matter?

Benefits of email testing.

Did you know that 1 in 10 emails aren’t accepted by the receiving mailbox providers? And that tested emails result in a 28% higher ROI?

That’s precisely why email testing is important.

In a nutshell, email tests ensure that your emails display and perform exactly how you intended. It enables email marketers to identify any issues with email design, layout, links, media, loading time, email rendering, inbox placement, and more.

By testing emails, you can check the quality and performance of your emails before sending them out and ensure that your email recipients receive flawless and high-performing emails only. As a result, your brand can maintain a good sender reputation and boost ROI through emails.

7 Key Elements to Consider While Testing Emails

Key elements to consider while testing emails.

Now that we’ve established that testing your emails can help you run successful and impressive email campaigns. Let’s get to the real deal: actionable tips to run email tests correctly.

Pay special attention to the following factors or elements while designing and sending your emails.


You wrote the catchiest heading ever, added a pop-culture reference for a little x-factor, and made sure to plug in your service or product as naturally as possible. And your email content is all set to impress your readers ... Or is it?

The problem is that even the best of us often overlook the basics.

Did you notice that? Yes, we're talking typos!


Make sure to test your email’s content for any spelling errors before you hit the final SEND.

An image showing editing multiple times reduces chances of error.

Spam Triggers

Testing email copy will also highlight if there are any spammy words in your content and prevent your emails from spam filters.

Words such as FREE, extra cash, don’t delete, and more are considered red flags 🚩for email service providers such as Outlook and Gmail. Hence, testing email helps you identify and eliminate these spam triggers.


You must rigorously test your email design for any formatting or design issues to ensure that the email template displays perfectly across all devices and email clients.

After all, you wouldn’t want all your efforts to design a chic-looking email to go in vain, right?

Plus, if you add media to your emails, such as images, videos, or gamification, test to check their quality and whether they perform well across all email clients or devices. Also, remember to test the email templates for their responsiveness.

A meme about the importance of responsive designs.

All of these worries could be catered to if you use an email design tool like Unlayer, which enables all users to design perfectly aligned and mobile-responsive emails in minutes.

What’s even better? Using pre-designed email templates with Unlayer can help you save more time and the hassle of testing emails for rendering issues.

CTAs and links

The call-to-action button in your emails is like a doctor’s prescription - telling readers exactly what they should do next for their benefit.

A meme about the importance of CTAs.
Source: Imgflip

So, when testing emails, remember to check whether the links in your CTA are clickable, functional, and properly sourced. Also, make sure that they’re clickable on smaller devices like smartphones.


According to WHO, approximately 1.3 billion people live with some kind of disability. That’s why testing your emails for accessibility is extremely important.

Funny meme about email accessiblity.
Source: Imgflip

While testing your emails for accessibility, check whether:

👉🏻 The email includes alt-text with images for people with visual impairments;

👉🏻 The attached videos don’t have an auto-play button for people with hearing impairments, and

👉🏻 The color palette doesn’t include contrasting colors for colorblind people.

If you want more information on how to make your emails accessible, follow the WCAG guidelines and make emails accessible for all.

HTML/CSS’s accuracy

Now, let’s talk about the backbone of the email AKA its HTML or CSS. Check that your email's code is correct and does not break.

Funny meme about email rendering.
Source: Instagram

To ensure your code’s quality, ask a colleague or teammate to peer review your code for you. Don’t forget to double-check whether your emails render correctly across all email clients and screens.

Send time

There’s a right time for everything, even sending emails. So thoroughly A/B test the right time to send emails.

Funny meme about email send time.
Source: Instagram

There’s no one right answer, so the right time to send emails may vary according to your target customers and the intent of your email.

Sender reputation

An area that is often overlooked during the testing phase is the sender’s reputation.

Funny meme about sender reputation.
Source: Linux Included

You should also set up the DKIM (DomainKey Identified Mail) and SPF (Sender Policy Framework) to ensure that the emails you receive are also authentic.

DKIM and SPF prevent the receiver from any phishing attacks or spammy emails.

Now that you know everything about the must-consider areas during the testing phase let’s see what the experts say about email testing.

And What Do The Experts Say?

To make sure you’re 100% ready to A/B test your email campaigns, we gathered some insights from experts regarding email testing. Let’s see what they have to say! 🗣️

⭕ Aspirational Email Subject Lines

Jay Schwedelson, the founder of tested the influence and results of various email subject lines and deduced that aspirational email subject lines result in 20% more open rates.

⭕ Do a Series of A/B Split Tests

Kath Pay, founder of Holistic email marketing, says, “Question everything you read. After questioning, if the advice still holds appeal, then do a series of scientific-based A/B split tests to confirm that it's the right tactic for your brand.”

Related: The Holistic Email Marketing Approach With Kath Pay

⭕ Deliver Value With Email Testing

Ann Handley, Chief Content Officer at MarketingProfs, believes testing emails enables marketers to discover what works best for their audience and ensures they deliver value with every email.

Concluding what these maestros have to say, A/B testing emails can be a game-changer for your email campaigns.

Want to know what we personally believe about email testing?

Our Hot Take on Email Testing  📧✅

We believe no matter how many emails you test, the results of one campaign should not be applied to every other email campaign.

Every email campaign is unique in its own way, so if 9 am proved to be the best time to send a promotional email, it is highly likely that the best time to send a holiday email is not 9 am but something else.

So, make sure to A/B test each variable for every campaign, individually and thoroughly. Also, leverage software will do the testing for you. To help you in this, we just listed the top three email testing tools of 2024 below. Have a look!

Top 3 Email Testing Tools You Can Use in 2024

Work smart, not hard. If you want to test emails while leaving no stone unturned, leverage these advanced email testing tools. All three of these tools are specifically designed to ensure that the quality and functionality of your emails are top-notch.

Let’s unveil these one by one.


Litmus is an email testing tool designed to enable users to send error-free and high-performing emails without investing time and resources in the email’s QA.

It is one of the best email testing tools out there and has quite advanced capabilities for an email marketer to leverage and enjoy.

Litmus offers a 7-day free trial. Their individual plan starts from $99/month; the small team plan starts from $199/month.You can contact their support team to learn more about their enterprise plan’s pricing.

Email on Acid

Another renowned email testing tool is Email on Acid.

Used by multiple enterprise-sized clients, Email on Acid enables users to test emails for issues such as rendering, typos, inaccurate links, etc.

You can preview your email to ensure its perfection and maximize your email campaign’s performance. Email on Acid is a secure and efficient email testing tool you can leverage for your email campaigns.

Email on Acid offers a 7-day free trial.Their basic plan starts from $74/month, the premium is $134/month, and the professional is $449/month. To avail of their enterprise plan, you can contact their sales team for more details.


Another option to make your emails flawless and ready to reach your precious customer’s inbox is Mailtrap. It's an ideal fit for freelancers and individual email marketers.

Like the above-mentioned email testing tools, Mailtrap is an excellent solution with advanced capabilities to test your emails and ensure that they’re error and spam-free.

Mailtrap offers a free trial. Their individual plan is for $10/month, and business is for $85/month.The Mailtrap enterprise is for $750/month, and you can customize your plan if you want to by contacting their support.

Design Emails That Perform and Display Perfectly

With Unlayer
Email Templates

FAQs About Email Testing

Want to know what others think and ask about email testing?

We’ve answered some frequently asked questions for email testing that you might find insightful, too.

Q. How to test emails with dynamic content?

If you want to test an email with dynamic content, you can leverage an email testing tool like the Email on Acid or Litmus. Once used, test the email for responsiveness, accessibility, personalization, and rendering.

Ask your colleagues to cross-check for you and ensure that it displays well across all email clients and devices.

Q. How can one optimize emails for better deliverability rates?

To improve your email’s deliverability rate, you must maintain a positive sender reputation, ensure that your email list is clean and active, use double opt-ins, and follow authentication protocols like SPF and DKIM. Lastly, make sure you engage with your subscribers regularly.

Related: How to Improve Email Deliverability With Keith Kouzmanoff

Q. What new approach should one consider while testing emails in 2024?

Real-time testing tools, advanced accessibility tests, leveraging predictive analytics, and increased focus on privacy and compliance are trending in terms of email testing.

Wrapping Up

All set to test emails for perfection?

Just incorporate the above-mentioned tips, advice, and best practices, and your emails will be ready to rule your subscriber’s inbox.


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