We know. Testing isn’t the most exciting stage of an email marketing strategy.

But it is essential, nonetheless.

Email testing helps marketers to understand how specific elements in their email strategy directly impacts results and engagement.

And testing isn’t a one-off process. It should be conducted regularly so that marketers can continue to refine and improve their strategy and campaigns.

This is particularly important as consumer behaviour is changing and adapting so rapidly. And what worked for brands 12 months ago, might not work today.

To get you started on your testing plans, here are 5 elements in your email marketing strategy that you shouldn’t fail to test.

Subject lines

For many brands, subject lines are an afterthought. But they are one of the most important elements of an email.

Because if your subject lines don’t engage the reader, your emails won’t even be opened. And all of that hard work that went into crafting compelling copy and enticing imagery goes to waste.

Even worse, if a subject line is done badly, it could be the difference between an email landing in the inbox, or landing in the spam folder.


Consider testing specific topics alongside more abstract ones to determine which piques your recipients’ interest. For instance, promoting a specific product vs commenting on the weather.


Consider if the language in the subject line is enticing. Test asking questions, using emojis, or being a little controversial to grab attention.


For example, if a subject line is too long, it could end up being cut off on mobile devices. If it’s too short, it can fail to convey the right message.


Using a simple personalisation tactic such as first name or location can be all it takes to grab the recipient’s attention.

Subject Line Example

Preheader text

Close behind in order of importance is the preheader text.

This piece of copy is often overlooked by marketers entirely. But preheader text is prime inbox real estate. It is the perfect complement to a subject line. And an opportunity for brands to offer more context to encourage recipients to open.

Mobile devices

42% of emails are opened on mobile devices, so ensure your pre-header text is optimised for mobile so that your entire message is seen.


Test whether using pre-header text as an extension of your subject line generates better results. Or whether focusing on a completely different topic is more engaging.

Inclusion or exclusion

Whilst we recommend making the most of pre-header text, it is worth testing to checkif including this copy generates a higher open rate.


One of the most common questions we get asked is “when is the best time to send an email?”

And the answer is – we don’t know. But we can help you find out.

The best time to send an email differs from brand to brand. Industry to industry. Audience to audience.

And the only way you can determine if your engagement rates are better on a Monday at 9am or a Friday at 4pm, is to test.


The obvious place to start with testing email timing is the day of the week. If you send out regular emails, such as newsletters, these are ideal for testing this element. Or review when your recipients are more likely to spend money, such as over the weekend.


Of course, time can also make a huge difference. For instance, are your recipients likely to be too busy first thing on a Monday morning to read your email? Maybe they check through their inbox at the end of the week whilst they’re wrapping up?

Start sending early

For email campaigns that are based around holidays, such as special events and festivities, it’s useful to identify a schedule for when best to begin sending these emails.

So don’t wait until the last minute to send your campaigns. Start a little early this year, and test when your engagement rates pique. This will help you to schedule your campaigns in the years to come.

Testing Time of Day Email Marketing Example

Copy and content

You’ve achieved that all important open. Great news! But the hard work isn’t done.

The copy and content within an email is what the recipient has opened for. So to keep them engaged, it has to be good.


Some audiences may prefer their emails short and snappy, with more emphasis on visuals. Whereas others may find more worth in longer copy which is more detailed and informative.

Types of offers

Do audiences respond better to personalised promotional codes, generic sales, or discounts on specific items they may have browsed?


It’s often easier for brands to send a one-size-fits-all email to all of their audience. But this may not generate the best results. Instead, brands should test out different personalisation tactics within their emails.

For instance, instead of recommending the same product to an entire audience, use dynamic content blocks to recommend products using browsing or purchase data.

Testing Copy Email Marketing Example


Last but not least, the design of your email will be the most striking element once your recipient opens. So don’t disappoint them.

From the email banner through to the colour of the call to action (CTA). Even the smallest changes to email design can make a big difference. Making it one of the most extensive email elements to test.

Design style

Your design style will be the first thing that recipients notice. So if you have the resource, test out different approaches, such as illustrations vs photography. You can even test categories within these styles, such as abstract vs people photography.


Colours evoke different responses in different people. Greens are meant to be calming, whereas reds are meant to encourage an action. Test your email colours to strike the right balance.


The amount of columns included in your design can have an impact on the readability of your email. One column may be easier to read, but feel a little lacklustre. Whereas too many columns could confuse the reader and make copy illegible.

Text size

Text size also helps the recipient to understand the hierarchy of your email. If all of your copy is the same size, emails can look overwhelming. Whereas by testing different text sizes, recipients will understand which copy is more important, and be able to skim through the email easier.


There is so much that can be tested with a CTA alone. Colour, copy, size, shape. Start simply by testing out each element at a time so you don’t become overwhelmed. We’d always recommend beginning with colour, as this can be one of the most striking elements of a CTA.

Testing Design Email Marketing Example

Need support with your email testing?

At Pure360 we offer an all-in-one AI email and web marketing platform alongside a Customer Success Team whose sole mission is to get you better results.

Get in touch today to find out more.