Email best practice

Updates from Gmail and Yahoo: DMARC

Gmail and Yahoo have both recently announced significant changes that will impact email senders, emphasising the need for enhanced authentication, decreased spam rates, and streamlined unsubscribe processes. As we delve into the upcoming modifications, it’s crucial for UK-based agencies to stay abreast of these alterations to ensure optimal email deliverability.

Authentication requirements

Gmail and Yahoo are tightening their grip on email authentication, requiring senders to configure both SPF and DKIM. This dynamic duo not only fortifies against abuse but sets the stage for the implementation of DMARC. For bulk senders exceeding 5,000 messages daily to Gmail, a DMARC record becomes mandatory, signalling a move towards a more secure email ecosystem.

It’s imperative to assess your current authentication practices and engage with your ESP to make necessary adjustments. The introduction of DMARC provides a strategic approach, beginning with a “none” policy before progressing to enforcement, a nuanced tactic to ensure compliance without disrupting existing email programs.

Spam complaint rate threshold

Sending wanted mail is paramount, and consent plays a pivotal role in user interactions. Gmail, in particular, has set a ceiling of 0.3% for spam complaint rates, signalling a tiered approach to consequences. Monitoring complaint rates through platforms like Google Postmaster Tools and Yahoo’s CFL provides valuable insights into program performance, enabling proactive adjustments to avoid inbox issues.


Simplifying the unsubscribe process is a key strategy to combat complaints. The introduction of List-Unsubscribe functionalities, including a one-click option, aligns with the overarching theme of making email management seamless for users. Notably, unsubscribes must be processed within two days, surpassing the CAN-SPAM requirement of 10 days, showcasing a commitment to exceeding legal standards.

What’s new?

While these standards have existed for years, the enforcement of these practices is a response to the persistent challenge of non-compliance. By implementing stringent measures, email providers aim to incentivise adherence to best practices, ensuring that non-delivered emails do not compromise revenue, awareness, or loyalty.

Looking ahead

These changes from Gmail and Yahoo are just the beginning. Expect similar stringent requirements from other providers as the industry unifies to create a robust defence against spam. As we approach February 2024, Gmail and Yahoo are cognisant of the need for a gradual transition, allowing senders to adapt without facing abrupt disruptions.


Adapting to these changes is essential for maintaining a successful email program. Our team is here to support you through this transition. For more details on the new requirements, visit Gmail’s Email Sender Guidelines page or consult Yahoo’s Sender Best Practices. Remember, you’re not alone in this journey, and together we can navigate the evolving email landscape. Blame the bad guys – spammers ruin everything!

Email best practice

Deliver the goods with good delivery

Maintaining a decent delivery rate can be hard enough at the best of times in email marketing, but it becomes increasingly difficult when you factor in busy sales periods like Black Friday or the festive period. Black Friday used to be just the one day, then Cyber Monday and you couldn’t do a whole lot of damage to your reputation across two days. But now companies have found to compete in the crowded retail market their campaign needs to span weeks, if not the whole month! That is a lot of emails for one person to get from a company and imagine how many they will get from all the marketing they are signed up to!

Deliverability tips

In a normal state of play, the best way to keep your email hygiene as tip top as possible may include the following:

  • Ensure you have correctly configured SPF, DKIM and DMARC records set up for your domain otherwise your emails may get quarantined or outright rejected and your delivery rate will plummet.
  • Ensure permanent bounces and all unsubscribers are removed.
  • Be willing to remove persistent soft bounces – they will never engage and only do harm to your send reputation.
  • You can sign up to receive the complaints back from such ISPs as Hotmail and Yahoo e.g. people hitting the “This is Spam” button and remove those.
  • Be willing to remove people that haven’t engaged with you for a particular period, e.g. 1 year, as again these emails will only harm your sender reputation and aren’t interacting with your emails. You can always attempt to re-engage them with reactivation campaigns.
  • Ensure you have a regular, steady flow of emails going out for ISPs to recognise the pattern from you which keeps them happy. Sudden changes, like massive volume spikes, may make them suspicious and less inclined to deliver your emails.
  • Targeting your users with personalised content is better than the “spray and pray” method to everyone. The engagement rates will be much higher and keep your sender reputation in good health. AI and data analysis can help you divine much about your users and only send them campaigns about things they actually like.

The above are a must for good delivery rates and list hygiene. But you may need to go a little further to survive busy sales periods unscathed.

A delivery tightrope walk

To ensure you get the best out of your sales campaigns whilst maintaining the health of your mailing list is no doubt a perilous balancing act. The temptation could be to send to as many people as many times as possible through fear of missing someone, but this method could have a disastrous effect on your sender reputation if complaints and unsubscribes come in their droves.

If you stop delivering to everyone, you are going to start missing out.

So what can be done?

Step 1: Warm up your IPs

The best thing you can do in the lead up to big sales events and an anticipated rise in email volume is to gradually increase your normal volumes and/or frequencies so there are no big spikes when the big push comes. If you want to know more about how this works, see our Black Friday-specific tips.

Step 2: Get your user preferences

Ask your users what they want! You will save a percentage of the data you would otherwise have lost if you provide a preference centre (even a temporary one) so your users can say how often they want to hear from you and on what topics (or even if they want to at all during the sales frenzy that is Black Friday). You may end up sending to fewer recipients as a result, but you should be sending them stuff they want which should increase engagement, reduce opt-outs and give your sender reputation a boost to keep your delivery rates ticking over.

Step 3: Stand out from the crowd

If people are receiving email after email that’s just piling up in their inbox, you need to stand out and be relevant to them. Getting people to engage with your emails is one of the best ways of maintaining a solid sender reputation and increase the chances of getting your email into the inbox, and not sidelined to a secondary tab, or worse, the dreaded spam folder. This will involve well crafted subject lines and as many tricks as you can rustle up, for example, why not check out Gmail’s promotion tools?

Step 4: Resend to non-engagers

With the aforementioned ever-growing pile of emails in people’s inboxes, even if you’ve done your best to get your customer’s attention you still may get missed. There is no harm in a second bite of the cherry by way of a resend to non-engagers, perhaps with a shiny new subject line, but this may well be a juggling act once again. You will inevitably pick up more unsubscribers for every send you make, which is an unavoidable hard truth in the art of email marketing, so you need to weigh up acceptable losses versus potential gains to work out the best strategy for you.

Forewarned is forearmed – you know how customers will feel throughout intense sales periods so make sure you do everything you can to keep them happy and nurture your relationship with them. Even if it feels like your strategies lead you to sending less than the maximum number of emails, the quality will be better and should produce better results whislt maintaining your list hygiene and see you through unscathed.

Email best practice

Your email marketing accessibility checklist

It’s the 2020s. Your marketing emails need to be accessible. It’s an ethical and legal obligation. Actually, scrap that – it’s simply the right thing to do.

But there are a lot of accessibility considerations, and therefore a lot of things to accidentally overlook. Here’s a handy checklist to keep your emails on track.

Use proper text

Images of text is awful practice and a major barrier to accessibility. Don’t do it – ever.

Use a minimum body copy font size of 16 pixels

That is generally agreed upon to be the smallest acceptable size for body copy. A bit bigger is even better. And it’s worth getting out of old habits of rendering footer content in miniscule lettering. If something is important enough to include in an email, it’s important enough to be readable.

Left-justify paragraphs of text

Centered text is fine for headings and calls‑to‑action. Larger blocks of copy, however, should always sit to the left. It’s easier on the human eye and an easily-implemented accessibility improvement.

Code semantically

HTML is full of descriptive elements like <h1> for primary headings and <footer> for, well, footers. Use them. Alternatively, you may wish to consider their ARIA equivalents.

Describe your tables

Add role="presentation" to every table that makes up your email (unless it is actually a data table of course). The HTML <table> element is repurposed in emails for structure rather than data, so make sure it’s marked as such.

Use responsive code properly

Your email’s content should fit to any screen size. But if you need to resort to cheating – i.e. doubling up blocks of content with separate desktop and mobile sections – then your design needs to be re-evaluated.

Use high contrast colouring

Low contrast can be difficult for a visually‑impaired person. Make sure your text, buttons and images stand out. How do you know if the contrast is sufficient? Try running your view online link through the Web Accessiblity Evaluation Tool.

Use high‑resolution imagery

Low resolution (or actual size) images look blurry on modern high density screens. Make sure all of your images are saved at double the maximum logical resolution at which they’ll appear in your email.

Optimise your images

Big file sizes + email is not a good combo. Mobile users in slow network areas will experience sluggish download times and potential broken images.

Describe images via alt tags

Readers using screen readers won’t know what your images depict unless you describe them. Developmental laziness excludes customers. Take a few seconds to type photograph of this or illustration of that.

Use blank alt tags on decorative images

But don’t waste your reader’s time by tagging images as decorative curve or suchlike. It’s just fluff.

And keep decorative images to a minimum

The more complex your design, the more section‑hopping a screen reader needs to perform. Not to mention the greater the chance of your email breaking. Web is the place for fancy. Email works best with a little more restraint.

Prepare for non‑animated animated GIFs

Outlook doesn’t like GIFs. It’ll only show the first frame. If something essential sits later in your animation, not everyone will see it.

Go easy on the GIFs

TV shows are announced with a warning when strobe effects or other flashing colours are coming up. You don’t have the luxury of forewarning people in email, so keep your animated GIFs gentle.

Use PNG images with transparency

Logos, icons and other non‑rectangular images can be unexpectedly left sitting in blocks of colour on dark mode. Use PNGs with transparency instead to let them blend naturally.

Don’t put critical content in background images

Because background images in email have a flaky history. Use them for cosmetic purposes only, and make sure your email still looks good if it falls back to a flat colour.

Maintain a consistent layout

It’s fairly popular in email to have alternating left/right layouts for images and text from story to story. Because it… looks cool? But from a screen reader’s perspective, the layout is confusingly inconsistent. A uniform design is much easier to navigate. Oh, and don’t be tempted to mess with the page’s tab index sequence instead!

Use plenty of white space

Too many things crammed together is visually distracting. Space items apart and give your design room to breathe.

Don’t cluster links

Text links or other small elements should never be close to each other. It’s confusingly fractured, and a finger pressing a touchscreen is liable to hit the wrong one.

Big buttons

Your major links should be presented as large, easy‑to‑press buttons. That keeps them both visually and functionally prominent. For maximum accessibility, make sure they are clickable all over and not just the text in the middle.

Design and code for dark mode

Oh, and on that topic – make sure your email is explicitly coded for dark mode. That means a carefully selected alternative colour palette and possibly substitute images in places that make sense.

Write concise copy

Rambling passages of text are not well‑suited to marketing emails (great for blogs though!). Tell people the essentials and let them click through to a website if they’re interested in the full story.

Don’t use cryptic subject lines or preheaders

Open-bait subjects don’t do anyone any favours. Respect your customer’s time by letting them know in advance if a message is worth opening.

Use descriptive calls‑to‑action

Ambiguous and mixed links are common in email. Often a feature’s image links to a different place than its button. You may know what goes where, but your customer does not.

Don’t overlink

Linking every square inch of your mailing to a landing page is frustrating for the end user. Only link calls-to-action or images that make logical sense. Paragraphs of text do not warrant links!

Keep your code under 100KB

Or your email will be clipped in Gmail.

Always include a view online link

Your email may be rendering perfectly in all of your tests, but that’s not the point. Your user may prefer or need to view it in a browser for personal reasons.

Don’t send from a no-reply address

Email is a communication tool. Don’t send the wrong message by making it a one-way street.

Send relevant content

Segmentation and targeting isn’t the most obvious aspect of accessibility, but it is one nonetheless. Presenting people only with relevant information helps to ensure that your mailings feel inclusive.

Test, test, test

Testing deserves a checklist all of its own. Broadly speaking, the following accessibility aspects of your email need to be checked for every send:

  • Visual check: the most obvious one. Your email needs to look presentable on as many devices and email applications as possible. A bank of real devices and/or previewing service like Litmus is a must.
  • Screen reader check: knowing how your email sounds is often overlooked. Look out for phrases like “2X points”. That may make sense when read, but when spoken it’ll sound like “two x” than “two times”.
  • Dark mode check: if you check light mode only, you’re only getting half the picture. Always take the time to check your email in forced dark mode environments like Outlook, and in controlled dark mode environments like iPhone Apple Mail.
  • Images-off check: your email needs to remain perfectly understandable even if images fail to load – which can happen for various reasons.

Is that everything?

Probably not. Accessibility is not black and white – it’s a scale. But the good news is that you don’t need to produce the perfect accessible email overnight or indeed ever. Every step towards more accessible emails is a victory in itself.

Email best practice

Let Outlook be Outlook

Microsoft Outlook is notorious in the email marketing world. It doesn’t do modern HTML and CSS. It has a thing for splitting emails apart at the seams with rogue white lines. All in all, it’s a pain.

But that’s ok. Here’s why.

You can’t repair software via an HTML email

Outlook is a desktop application. The kind that’s coded in a complex language like C++ or suchlike. Oh, and it uses Microsoft Word – yes, the word processor – as its rendering engine.

A remote email developer has the following tools at their disposal: HTML, CSS and VML. None of these are programming languages. Their purpose is content and presentation. Therefore none of them can be used to re-engineer Outlook’s functionality. The best that can be done is to circumvent Outlook’s quirks and take steps to minimise their chance of occuring.

Acceptance ≠ apathy

Accepting Outlook’s limitations doesn’t mean doing nothing about them. Marketing emails should be designed and coded to degrade gracefully. That means designing and coding in such a way that your email can be progressively simplified and still look presentable.

Your reader probably isn’t using Outlook

Are you in the B2C market? It’s likely that only a tiny portion of your readership is using the desktop Windows application. Outlook has a mere 4% market share.

As you’d expect, most Outlook users will be present in the B2B sector. This however is no reason to panic. Design and develop accordingly.

Outlook can mean many things

It’s a Windows application. Plus there’s an online interface for Outlook 365. There’s also a Mac version that is quite different in every way. Oh, and there’s the webmail service. And its associated mobile app. With iPhone and Android flavours of course.

We’re not done yet. The Windows application has various editions. 2013, 2016, 2019 for starters. How these render your emails can even change according to screen density. Have you lost count of all the Outlooks? I have.

Your subscriber doesn’t care (so neither should you)

Email is a transient, fleeting thing. Its purpose is to communicate a message or an offer swiftly and clearly. Looking pretty is secondary.

That doesn’t mean it’s not worth the effort to design great‑looking emails. It is. It’s even worth a bit of effort to sort out Outlook problems.

But what is not worthwhile is frittering hours and hours of your time to get rid of a 1‑pixel glitch in one version of Outlook. Your customer is interested in what you have to offer. I can’t guarantee that they won’t notice a trivial rendering glitch, but I’ll bet money on the fact that they won’t care.

Example of a rogue white line in Outlook
White line: campaign-stopping crisis or trivial fact of Outlook life?

Time is money

This is business and we’re all here to make money. Investing resources on trivial matters is a poor effort‑to‑reward payoff.

If you’re sending a richly designed mailing, you’re likely to trigger an unwanted rendering glitch in at least one version of Outlook. From an email developer’s perspective, the cause is purely down to chance – as is the solution. And that solution could potentially take hours to unearth, if even possible. Accept it as a triviality and move on to something more important.

We’re stretching the medium beyond its intended capabilities

Email used to exclusively mean a letter‑like digital message sent from one person to another. Probably with some kind of hilarious cat joke, and possibly a threat that something awful will happen if you don’t forward it to ten friends. As a format, email consisted of words typed on a plain background, perhaps with a picture or two attached for download. That’s what email was.

At some point along the line, the technology became (somewhat) intertwined with the HTML and CSS code that powers the web. That afforded significant improvements in styling and branding, which is nice. But the pendulum has perhaps swung too far. It’s now common for companies to send marketing emails that resemble mini‑websites – a far cry from its electronic mail origins. Should we be surprised that it breaks?


Outlook isn’t all bad. Seen through the right lens, it’s a reminder to focus on content rather than decoration. Follow best practice in your emails and let Outlook do what Outlook does.

Email best practice

It’s a feature, not a bug: email edition

Are those pesky email applications messing with your design? You didn’t want that address to be automatically linked to Maps, and you certainly never asked for telephone numbers to be underlined! It’s time to squash the bugs.

The battle begins

Overriding a piece of email software’s functionality often isn’t a simple task. The only tools at our disposal are HTML, CSS and a bit of imagination. Email development forums are awash with questions and suggestions on this topic, plus a graveyard of now-defunct solutions. There’s much trial & error, and the successful method usually amounts to some kind of hacky trick.

Here’s an example. Some versions of the Outlook mobile app will recognise and auto-link dates and times to the user’s calendar. This also turns the associated copy blue. One effective solution is to secretly break up the text with an invisible special character called a zero-width non-joiner. Congratulations – you have successfully tricked an application into losing functionality!

Don’t fight functionality

But why would anyone want to do that? The fact that there’s often no easy ‘fix’ for these ‘problems’ says a lot. The problem does not lie within the application’s functionality. It lies within the sender’s design and objectives.

Suppressing a piece of functionality is not in the spirit of accessibility. And to be frank, it’s not the sender’s decision to make. Nobody likes it when a website blocks or forces the opening of links in new tabs. A similar etiquette applies to the world of email.

Design around it

Addresses are another type of content that could be auto-linked and coloured blue. If they’re sitting on a coloured background, that could result in an ugly clash and illegible text. The solution: place them on a white background instead. Cosmetics do not trump usability.

Example of address in an email being auto-linked to maps
Outlook has helpfully linked that address to the maps application. Should we break that… or change our background colour instead?

Reallocate the effort

I mentioned trial & error earlier. That means editing code, uploading it to an email platform, sending tests, and checking them on real devices and/or previewing services. All of this all takes time. But this is not a task that deserves it.

Imagine what could be created in that time rather than destroyed. Optimum email designs. Improved accessibility. Better content. Don’t squash the ‘bugs’ – give them a better habitat instead.

Email best practice

Simple email design for a fragile medium

Google recently caused a ruckus in the world of email marketing. As part of an update to Gmail, support for background images was (accidentally) knocked out. Oops. The result was an industry of marketers in panic.

Email developers scrambled to find a fix. Workarounds were found, and Google ultimately resolved the fault at their end. Crisis over. This incident will soon be forgotten – which is a pity, as there lessons to be learned.

Things change

This isn’t the first time such an event has occurred. Changes to email platforms are fairly regular. Sometimes for the better, sometimes for the worse. I recall at least two times when a major email platform made a change that immediately broke responsive stacking content on mobile devices.

Or how about some ancient history? In 2007, Microsoft made the infamous decision to switch its ubiquitous Outlook application from a web browser-style rendering engine… to one based on Microsoft Word.

These sort of sudden, unexpected developments vary from subtle to industry-changing. But they have a couple of things in common:

  • They are beyond our control as email marketers.
  • The more complex the email, the greater the chance of it being affected.

Ours is a diverse but fragile digital environment

One customer is viewing your email in Apple Mail on an iPhone 14 Pro Max in dark mode. Another is looking at it in the Gmail web app in Firefox on Windows 10. Someone else is using a little-known third party Android app on a flip phone. The point – there are countless devices, platforms, versions and personal settings to cater for.

Now add Outlook and its archaic code support to the equation. With all this in mind, it’s clear why HTML emails can only work thanks to an array of coding tricks and extensive ongoing testing. The more complex the design, the more liable it is to break now or in the future.

Overloading the medium

Like all email developers, I’ve been faced with many moments of hair-pulling frustration. Inexplicable gaps in emails, font problems, wrestling with truncation… the list goes on and on. This raises a question – why are we going to all this trouble?

Thinking specifically about the Gmail background troubles, I cannot imagine any email content in which a background image is essential. Nice, sure. Fancy, sure. But essential, no. As a means of conveying useful information to a customer, a regular image and some text will do just fine.

Comparison of a resort image with overlaid text and with text underneath

All of this boils down to the fact that email is far more fragile than a website. And that is not a bad thing. The trouble only starts when we try to force email beyond its capabilities.

Simplicity is key

Most email development struggles are of our own creation. Why battle for hours to achieve a particular design when the easier option is to simplify? This isn’t admitting defeat. It’s making the smart choice to design for the medium, rather than trying to shoehorn a pseudo-website into an email.

Neither does it mean making an ugly email. Simple is not a synonym of dull. A simple email can include static images, and a static image can be as eye-catching and complex as you desire. The email that houses them doesn’t need to be convoluted, and will only benefit from simplification.

Complex email design is less accessible

The hidden beauty of accessibility is that it benefits everyone. The design and coding techniques that it involves will often directly improve your overall email, or serve as a reminder to clean it up.

Complex email design is the enemy of that. It increases the chance of colour clashes, screen reader navigation difficulties and inconsistent use of text and images to communicate information. Simplicity in design means that we don’t have to strive to find clunky solutions to these problems – we circumvent them entirely.

Email code is absurd

It’s easy to forget just how ridiculous email code is. HTML data tables are used for structure. Multiple nested elements are used to achieve something that could be done with a single HTML tag on a website. Spacer objects are often required to force items into place. An assortment of tricks and hacks loosely pins everything together.

And yet we repeatedly choose to attempt complex designs in this environment. Surely the logical choice would be to have less of this clunky code, not more?

Email designers are their own worst enemy (or at least the email developer’s)

Mobile phones have some fairly decent photo editing apps. But they’re no replacement for Photoshop on a desktop computer with a mouse or tablet. The mobile apps are suited to quick, simple edits only. Trying to do anything more in-depth is convoluted if not outright tortuous.

Designing emails that look like websites is like trying to perform complex photo editing on a mobile. It’s simply not the right tool for the job.

Breaking from convention takes courage

Almost every brand sends fancy HTML emails. Companies need to adhere to brand guidelines. No-one wants to challenge the status quo.

That could be good news for you. The one who breaks convention reaps the rewards while others struggle on. Be that one!

Email best practice

How to figure out when is the best time to send your email campaign

It’s a question that comes across our desk almost weekly, “When should we send out the email, when is the best time?” – The answer as with so much in email marketing is… “it depends”. Working out when you should send an email is really unique not only to the company sending it but even unique to the content of the email itself. If your goal is to increase your engagement rates then you are going to need to work out when is the best time to send emails.

We have been sending out emails for quite a few years now and to say ‘we’ve seen it all’ would be a bit of an understatement. With over 5 million emails sent every month by myself alone. Therefore we can say with a great degree of certainty that there is no one perfect time to send an email. The best time really does vary from industry to industry, business to business as well email to email. Unfortunately for you dear reader there is no singular time that is best for all emails to be sent. Although that would make all our lives a lot easier.

The main goal of any email is to drive traffic to a website. This email engagement can only be improved if every part of the email is carefully designed to suit the audience. This includes everything from the pre-subject line, copy, design, email length, buttons and even the send time.

Test, test, and test again

Getting email engagement to increase really does require quite a lot of different tests. This includes testing the send time, subject lines, copy, design, and other key elements of the email. Ideally each aspect of the email is tested one part at a time as to not cloud the results from any specific test.

Having so many things to test and evaluate may seem daunting at first but by systematically working through each with a number of A/B tests you should start seeing patterns of engagement. Make sure to test one aspect at a time and also try run 1-3 A/B tests per item so you are sure of the results. Employing other tools like our subject line creator tool can also assist with this process.

1. Divide your list into segments

The first step is to divide you database into smaller segments. Ideally the divisions are not arbitrary but based upon matching characteristics such as, purchase history, geographic location, age, gender or as many matching characteristics that seem relevant. Hopefully by grouping similar subscribers together they will produce less random results and make testing to those segments more accurate.

Most email marketing platforms have segmenting tools built in and if not we can assist with any data segmentation you might require.

2. Create your tests

With your newly created segments it’s time to start testing. It is important to be able to measure the success of each test so try not to test multiple things at once. Always be goal orientated with each test. For example, “Does placing high value products near the top of emails result in higher sales for these item?” Make sure you tests are also based on some real world knowledge, for example people will always spend more closer to pay day. So this might skew some results if you’re testing close to those days. Try and isolate your tests as much as possible.

It is also important to also build on the findings of your tests. So for example if your Sales email is always the most profitable email and you know people spend more on payday. You should certainly then test if your Sales email is more effective if sent closer to payday.

3. Divide each segment into control and test groups

Once you have decided what you are going to test divide each segment into two equal numbered sub-segments. Your ESP should be able to do this for you. It is important to ensure each sub-segment is large enough to produce meaningful test results. If you think the segments are too small you might want to adjust what you are testing or add more data. The final option would be to run more tests to remove and randomness from the results. There is also a useful calculator you can use to calculate a good size

4. Create two versions of the email

To make the test create the email as you normally would then create a version that will test your hypothesis. This can be anything such as reordering of content, subject line, overall design, button placement.

5. Measure the results

Ideally your ESP has a robust reporting suite or heat-map capability. This should allow you to easily see which email generates more engagement as well as allowing you to see what element of the email is generating all the clicks. To really make sure of the results you could run 1-3 additional tests, testing the same thing to remove and randomness from a one off test. For evaluating send times make sure that you’re getting the same type of engagement you would expect regardless of when you send the email. Then choose the send time that gets the most engagement.

Build on the wins

Now that you have established the best time to send or any other aspect you have been testing implement these results on the main database sends. As long as the results are replicated in the main sends you are good to begin at the beginning of your testing cycle again. Testing should be a consistent practice that you continuously include into you marketing calendar. Remember also that just because a Sale email might perform well close to pay day doesn’t mean you should send your welcome emails out then to. You might find Welcome emails perform better if sent only 30 minutes after sign-up.

The key point with trying to improve engagement through email testing is to remember to constantly tailor your tests and ultimately your approach to your audience. Use your educated guesses to guide your questions and then make decisions based on the real data you get back from tests.

Email best practice

Email accessibility: are you leaving anybody out?

Communication. That’s what email is all about. The same is true whether you’re using it to apply for a job, or to seek help from customer services… or to market your product to thousands of customers.

Marketing emails typically go to lots of different people using lots of different devices. Your objective is to convey an equally intelligible message to all of them. That brings us to the concept of accessibility.

Defining email accessibility

Firstly, here’s what accessibility is not:

  • An inconvenience
  • An afterthought
  • Exclusively a matter of visual impairment

And now for what it is. Mozilla (the developers behind the Firefox web browser) describe accessibility as: the practice of making your websites usable by as many people as possible.

Applying this thinking to our favourite medium, it means emails that can be easily understood, navigated and interacted with. We want our mailings to render optimally in any application on any gadget. They must impart a clear message and invite a defined action from the customer. And accessibile emails are open to people whatever their level of physical ability.

Email accessibility is a huge topic, encompassing many human and technical factors. Let’s take a look at some of them.

Clarity in message, design and function

A marketing email usually performs two main functions:

  • Communicates a message to your customers.
  • Invites them to take action in response.

Concise copy and a user-friendly structure support those objectives. Worry not – that doesn’t mean your email needs to be sterile and unimaginative. There’s still plenty of scope for characterful writing and vibrant imagery. The art is in creating an eye-catching design that supports your message rather than overwhelming or obscuring it.

Accessible copywriting begins with the subject line. Good, honest information beats vague open-bait every time.

Image of good and bad versions of an email subject line

I like big buttons and I cannot lie

There’s a tendency in email marketing to go link-crazy. Every heading, every subheading, every image, every block of text… and even empty space – all clicking through to web pages. That usually means ambiguous destinations and multiple links to the same places. The technical term for this is a mess.

The solution: buttons. Big ones. Big ones with clearly defined calls-to-action. Your customer should know in advance what sort of content to expect upon pressing it. And don’t forget to include plenty of breathing space around those buttons. You don’t want links to different places squashed up against each other, especially on touch-screen devices.

Don’t get left in the dark

Dark mode took off a few years ago, and remains a popular display option among those who care about things like battery life and corneas.

It can have a dramatic effect on the way your email is rendered. And often not in a good way. Images can be camouflaged against recoloured backgrounds, or left floating in unsightly squares.

Email being email, the rendering methods for dark mode are not consistent from one email application to another. It therefore requires an assortment of coding and imagery techniques to create dark mode-friendly mailings. Dark mode-specific CSS classes are possible. PNG format images with border effects help them stand out, should they be unexpectedly displayed atop a dark background.

Comparison of a logo as seen in light and dark modes

The technical details are a complex topic for another day. But let’s be clear on the objective – you want to optimise your email for dark mode, not override your user’s preferences.

So many apps, so many devices

Sorry in advance, but I’m about to throw a bunch of words at you. Here goes.

Desktop computers, laptops, tablets, mobiles. Screen sizes, model versions, display settings. Desktop software, webmail services, mobile apps.

My point: there are many software and hardware combinations out there, and your marketing emails could be viewed on any one of them. You want your email to be just as legible on a dusty old laptop running Microsoft Outlook 2016 as it is on a brand-new iPhone.

Responsive email – i.e. that which is coded to fit to any screen size – is the answer. It’s standard practice nowadays, but that absolutely does not mean that it is always handled adequately. All too often, mobile rendering remains a secondary concern – leading to visual problems like tiny text and confusingly mismatched imagery. We’ve written extensively about responsive email in the past, but let’s sum up some of the most important points:

  • Plan your responsive design from the outset. The mobile layout should never be a secondary consideration.
  • Support for HTML and CSS in email is extremely varied and somewhat limited. An email developer must understand how to code effectively for all major devices and email services.
  • Be prepared to simplify an overly-ambitious design. Fanciness for the sake of fanciness is not in the spirit of accessibility.

Even if you’re confident that your email is perfection itself, always include a link for it to be viewed in a web browser.

Hear me out: your emails could be confusing to screen readers

I mentioned earlier that accessibility is not all about visual impairment. It is however an extremely important aspect, and will largely be the focus of the remainder of this article.

A screen reader is a piece of assistive software that will audibly describe the content of an application, web page… or indeed an email. You probably have a screen reader right in front of you right now. Press COMMAND + F5 if you’re on a Mac, or CTRL + WIN + ENTER if you’re on a Windows PC. While the use of a screen reader takes time to master, this will give you a helpful insight into how a visually impaired person might be interacting with your content.

As technically incredible as screen readers are, it is unfair to expect them to do all the work. A website must be designed and coded in a way that a screen reader can navigate and interpret. The W3C Web Accessibility Initiative (WAI) publishes extensive guideance on this topic, and a lot of the advice carries over to email.

Let’s take a look at some ways to develop emails with screen readers in mind.

Write semantic code

Do you shop in supermarkets? They have signage to help you find your way around the array of aisles. ‘EGGS’ here, ‘HOUSEHOLD ESSENTIALS’ over there. If those signs didn’t exist, your shopping experience would be a lot more frustrating. An email without semantic code is a bit like a supermarket without signs.

Semantic email code can be defined as meaningful HTML tags. These are the basic elements behind the scenes that make up a mailing. Here are a few important ones:

  • <header>
  • <nav>
  • <section>
  • <article>
  • <h1> (the main heading on the page)
  • <h2> to <h6> (increasingly minor headings – seriously, I don’t think I’ve ever gone past h3)
  • <p> (a paragraph)
  • <strong> (bold text)
  • <em> (italic text)
  • <footer>

But there are also multi-purpose, non-descriptive HTML elements:

  • <div>
  • <span>
  • <table> (for the presentational purposes of email, that is)

Those last three are far from invalid. But it’s easy to be lazy in web and email development alike, and rely on them too heavily. In fact it’s actually somewhat rare to code particularly semantically in email.

But guess what – descriptive HTML tags help screen readers know what’s what. Say your main heading is just sitting there in a generic <span> tag. A screen reader won’t know that it’s any more significant than any other text that happens to be floating about on the page. If it’s wrapped instead in an <h1> tag, the screen reader will announce it as “heading level 1”. Now the user better understands what is being communicated. Construct your entire email with semantic code and you communicate useful information to those who can’t see it.

Similarly, sequence is important. Screen reader users will often be using a keyboard to navigate through the email. By default this will jump from item to item in the order they appear in your code. Make sure it makes sense.

And while there is actually a way to override this sequence, doing so is so far removed from best practice that we will discuss it no further! Far better to construct an email that follows a logical sequence in content and structure.

Mark your bricks as bricks

Modern websites are constructed with the finest materials available – divs, spans and all sorts of CSS-styled goodness.

Emails are built using a more… rustic method. They use HTML tables for structure, just as web pages did once upon a time.

When a screen reader encounters a table, it assumes that it is a table of data. Something like this:

Image of a table showing populations of capital cities

A screen reader may therefore produce confusing results when dealing with the structural table of an email. There’s an easy fix for this. Just apply the following HTML attribute to all of the tables that comprise your email:


Congrats – you’ve just told screen readers what your tables are for, and made your email immediately more accessible.

Let text be text

When you write a text message to a friend, do you take a screenshot of it and then send it as an image? Unless you’re charmingly eccentric, I suspect the answer is no.

The same principle applies to email. And yet countless companies – sometimes even the biggest of corporations – produce marketing emails in this roundabout manner. Paragraphs of text are drawn up in a design application, saved as JPEGs and dumped into HTML emails. Why?

This practice is so widespread that phrases such as ‘live text’ have sprung up. Let’s get out of that way of thinking. It’s just text.

There are probably multiple factors at play here. Brand guidelines and typography. A desire to achieve complex layouts in a medium that doesn’t make it easy. Or it could be the it’s-always-been-done-this-way mentality.

Accessibility and usability trump all of those things. There are all sorts of reasons to use proper text. It renders sharply and at a consistent size, whereas images shrink and grow. Users can zoom in without the letters becoming blurred. Chunks of text can be selected and copied. And it’s the purest form of copy for screen readers to detect.

Web fonts are reasonably well supported in email these days, so you don’t even need to lose your brand typeface. Now all of the boxes are ticked.

Animated comparison of text and image versions of the same content being scaled

Pictures speak a thousand words

But only if you let them. And you should probably cut that down to a handful of helpful, descriptive words.

HTML comes equipped with a thing called alt tags. That’s short for alternative. These tags allow you to attach text content to any image on the page. We can use them to describe what is pictured or relay copy from a heading. Normally the alt tag goes unseen.

They are however of critical importance for users who cannot see your image. That might be someone who has chosen to turn pictures off, or perhaps the file has failed to load, or it could be a person with a visual impairment.

Take a look at a few examples:

Overhead aerial photograph of a hotel's outdoor pool, surrounded by trees and rooftops

alt="Overhead aerial photograph of a hotel's outdoor pool, surrounded by trees and rooftops"

Watercolor painting of a pink flower in a plain background

alt="Watercolor painting of a pink flower on a plain background"

Example heading saying SALE NOW ON


Without these descriptions, the content of these images would be completely concealed to a screen reader user. By typing just a few words, you have produced an immeasurably more inclusive email.

One more thing – emails often include some purely decorative or spacer images. Just leave the attribute as alt="", and screen readers will know to ignore them.

Self access-ment

We’ve covered a reasonable amount here, but this is a topic too broad to fully explore in a single article. There are plentiful accessibility resources online, even for the relatively niche branch that is email.

Among those are tools to analyse the accessibility of your web page or email. Some of these are commercial products, but there are also some handy free ones.

Paste in your email code at and you’ll see an instant report with suggestions for improving accessibility.

You might also wish to try WAVE – web accessibility evaluation tool. As the name states, this is intended for web pages. But much of the feedback also applies to email, so there’s nothing to stop you popping a ‘view online’ link in there.

Perhaps most useful of all is a simple checklist. That’ll let you score your emails consistently according to your particular requirements.

Here’s to more inclusive emails

Making your emails accessible is a complex task – but it doesn’t need to be an extra one. Accessibility standards are intertwined with email best practice. By putting accessibility at the core of your design and development process, you automatically produce better emails all round. Everybody benefits.

Perhaps the key to accessibility isn’t to think of it as a separate subject at all, but simply the act of making a good email.