Designing HTML emails
It’s 2017 and it seems that plain text emails are just boring for most users. Communicating without the emoji, GIFs or images seems rather stiff and your brand is better than that! It’s approachable and fun, or sleek and high-end, or in some other way remarkable. No plain text email will do.
How is email displayed?
The email is sent from a server to an email address that is hosted on another server. This server then shares the email with various email clients (e.g. the Mail app on iOS), that decide how to display the content. The server and/or email client can strip away some or even all elements that are not plain text - specific or all HTML tags, styles, images, links - leaving the user with the end content, that is then being displayed.
The main difference between an email and a website is that you can’t know what email client the user is going to choose and so you can’t send a specific version to each user - you send the same email to everyone. You can’t detect beforehand if it’s Firefox or Chrome, Gmail or Outlook, you can’t swap images for smaller versions on mobile. You send an email and it sits in your client’s inbox - as soon as they get it, you have no control over how it’s going to be displayed and can’t adjust accordingly.
Understand your users
If you ever went through building a static website or a web app, figuring out how to support the features you want in most browsers was hard enough. Nobody expects every web app to work perfectly on every setup - that would take insane amounts of work and give very low marginal gains. That’s why web developers are telling you they’re going to support the modern browsers like Chrome or Firefox and no-one in their right mind wants to support older Internet Explorers*.
Testing with tools like Litmus or Email on Acid will help you get a better grasp of how your design works in most popular email clients - but there can still be issues with clients that are not being tested by those tools. It is impractical to expect the email to work in all clients - that’s why it’s good to research how your clients are using email.
What webmail providers and/or email clients are they using? Which of those give you most marginal gains and you need to support them? Consider having a cutoff point for the share of various software in your client base - adding support for additional clients takes time and might also cost you some features, maybe it’s not worth doing for 0.01% of your clients.
How are they accessing their inbox? Do they read emails on their desktop or their phones? Decide if you want to design mobile- or desktop-first.
What email campaigns worked best for the measures that are important to you, e.g. how many of your users click links in emails? Think about the things you want to include in your email - you’re taking the time to design it, so make sure you’re not spamming your users with irrelevant content.
Focus on the content
There are many reasons your users will only read plain text emails - some of them do it by choice, some of them by necessity, e.g. if they are visually impaired, some simply use email clients that only support plain text. That’s one thing every email client does and they do it pretty well.
Before you design your email, take a moment to focus on the message - why are you sending an email to your users? If you were to strip away all the design, what should be included in it? How should you divide it into paragraphs and make sure the users get your message?
Assuming that your users will always be able to read the HTML version of your email might be overly optimistic. Don’t assume - assure that your message always gets through and use plain text as your main tool.
There are also things you should consider including in your email, to improve user experience no matter the client:
- subject - clear and concise, usually under 50 characters
- professional sender address and name - preferably with your company name
- pre-header text - some email clients present it in the inbox as a preview of an email
- footer - preferably with unsubscribe options
- link to a web-hosted version of the email
Add the design gradually
You might want to include more than just plain text in your message - your logo at the top, an image or a GIF that would make it more appealing, a nice button to encourage users to click the link.
Keep the design simple. Add it in gradually and make sure you always have fallback options, e.g.:
for every image have a fallback text that displays before the images are loaded, e.g. Gmail often loads images after a user action, so take the time to look at your design with placeholder text instead of images
many clients, including Gmail, won’t support custom fonts (unless the user has them already installed on their computer) - use web fonts to make the design more appealing on some clients, but always have a fallback option like
Helveticahandy; check how your design looks with the fallback font
if you’d like something slightly more fancy, like a video or an interactive element, keep in mind it won’t be supported in most email clients and simply link to it in your email in an appealing way
In web development, we’re getting more and more used to flexible, seamless designs that flow with the ever changing screen size of our devices. Emails, even though they use the same basic blocks of HTML and CSS, are not that advanced - to adjust for different devices, you need to make your design fluid rather than flexible.
Some email clients don’t support media queries - if you want to go from two-column design to a single mobile column or even just adjust the font size, keep in mind Android or any number of less popular mobile clients might not agree with you.
There are two main breakpoints in email - 600px for desktop and 320px for mobile - but the most bulletproof way is to avoid them altogether, by either using a device-agnostic single-column design or making your design fluid rather than flexible. Think percentages, not breakpoints, define margins and paddings rather than set sizes.
Don’t expect emails to be pixel-perfect - you might really like those rounded corners on your buttons, but making them work in older clients is going to take a lot of work using images and careful placing, that might break on some clients regardless of all the effort.
Start with a simple, flat design and add improvements for more modern clients, but don’t expect them to work across all devices. Just make sure that adding additional elements or flavors is not breaking your base design.
You can’t control your users - some users adjust their setups and increase the default fonts, make their displays monochrome or block images by default. You won’t know how your users see the email exactly and that’s ok - if you design with a fluid approach in mind, they’ll still be able to read your message and find the relevant information.
Mind the quirks
There are many effects and elements you might be used to that cause mind-boggling issues in HTML emails. Some of the more common ones are:
custom fonts - you can get away with web fonts, but not all clients support them; also, you have no control over user-specific settings, e.g. if they’re using an increased font in Android, the email client might render it regardless of all your efforts to avoid it
overlapping elements/layers - you can’t overlap elements in emails, other than adding a background image, and even that might not work in some clients, but careful use of whitespace might help you achieve a similar effect
putting text in symmetrical shapes - there are no flexible CSS properties to ensure the shape will stay symmetrical, so it’s better to use ovals than circles and rectangles than squares
hiding overflow - if you want to truncate text, do it before sending the email, as hiding overflow might be problematic
gradients - they won’t display in many clients and can cause a solid background color to obscure text
non-image shapes other than rectangles - some email clients won’t support border-radius for circles or rounded corners, most don’t play well with more complicated shapes - try to keep it simple with rectangles and/or images
This is not an exhaustive list, but it can give you some ideas on where to simplify your design.
If you have some experience with regular web development, you might expect the code to be written in a certain way. HTML email code breaks many of the best practices one gets used to.
In modern web development, using the
!importantkeyword too much (or ever) or inlining styles are often considered code smells. In HTML emails they might the only way to display the email as intended - it’s not uncommon to see an inlined style with
!important, just to force this one stubborn email client to render it properly.
Email code is not DRY - you can define both a
backgroundproperty on a table and add a declaration for the
background-imagein the inlined style for the same element, just because some clients support the table property, some understand only the
backgroundshorthand and there are those quirky ones, that only render the
background-imageif forced by a more specific declaration. Oh, and don’t forget about this class that also sets the
Arranging elements in email uses tables, which is the most widely supported HTML element across all clients. If you want to make sure your layout is going to work, the number of tables within tables can increase dramatically with each element.
Designing emails is different from designing websites - email clients have at best patchy support for CSS and often require writing code that breaks the best practices of web development.
Understand your users - have a list of email clients you want to support, understand what to include in your emails and how to appeal to your user base. Decide if you want to design mobile or desktop first.
Focus on the content - write a plain text email first, structuring it by using paragraphs, bullet points, links. Make sure to always include plain text version of your message.
Add the design gradually - the simpler the email, the better the chance it’s going to work well on multiple clients. Add in fallback for your features (images, fonts, videos) and make sure to check how your message looks using only the fallbacks.
Rethink flexibility - think fluid, not flexible. You can’t control how your user is going to see the design, so let go of pixel-perfect and make sure to design with percentages and paddings, rather than set sizes.
Mind the quirks - the simpler, the better. Email clients have many quirks and the more complicated the design, the higher the chance it’s going to look bad in some clients.
Reading code - email clients require you to write code that’s not in line with web development best practices. Get used to
!importantand loads of tables.
- Xfive 10 Tips for Better Email Design
- Tuts+ The Complete Guide to Designing for Email
- Sigstr How People ACTUALLY Read Your Emails
- Campaign Monitor CSS Support Guide for Email Clients
- MailChimp Email Design Guide
- Webdesigner Depot The ultimate guide to email design
*though it is sometimes necessary to support IE8, but that's mostly because target user group uses outdated software