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The majority of email clients don’t support every type of HTML content you see on the web. Web browsers are able to display scripts, animations, and complex navigation menus, while your typical email inbox isn’t built to handle this type of content.
In this article, you’ll learn about content types to avoid in your email designs, and what to use instead.
Email HTML v. Web HTML
View the table below to learn more.
Safe to use
Use with caution
Do not use
Safe to use: widely supported by most email clients
Use with caution: limited support from most email clients
Do not use: not supported by most email clients
Elements to Avoid
MailChimp's predesigned templates do not include elements that are known to fail in email inboxes. If you insert these elements with Code content blocks, our system will remove them to make sure your subscribers can view your campaigns successfully.
Use with Caution
Background images won’t display in every email client. Popular clients like Outlook and Hotmail automatically remove background images from your campaigns. If your background image is removed, your text content may not be visible at all if it’s lightly colored. Instead, insert a smaller image in your campaign.
Review our Design For Email guide for design ideas that are compatible with popular email clients.
MailChimp’s Drag and Drop Editor provides web-safe fonts only. Most email clients don’t support CSS properties like @font-face, @import, and that import custom fonts into web pages. For consistent display, use web-safe fonts.
Or use images to display custom-font headlines, and include the body content as text. Without this balance of text and images, spam filters can flag your campaign.
Your subscribers often open campaigns on mobile devices or in the preview pane of desktop email clients. Email viewing panes are narrow, so they’ll cut off your message if it’s wider than 600-800px.
Read our layout guide for tips and strategies for building narrower templates.
Do Not Use
The elements below are blocked by nearly all major email clients. Support is either extremely limited, or nonexistent.
Try gifs to make your content more engaging.
An <iframe> (inline frame) is an HTML element that embeds content from one website into another. Inline frames are often used to insert advertisements, video, audio, or forms in other websites. Iframes often contain scripts, so most email clients block them.
Instead, link to the content you want to display in your campaign.
Flash displays animations and graphics on websites, but most email clients block it.
Instead, try gifs to make your content more engaging.
Autoplay and click-to-play media won’t play in an inbox unless your subscriber’s email client supports HTML5 <video> and <audio> tags. Only one major email client, Apple Mail, supports these tags, so it’s best to avoid embedded media and consider an alternative.
If you’re comfortable with coding or if you have access to a developer, you can design custom coded templates that contain HTML elements with limited email client support, but we don’t always recommend it. Keep in mind that MailChimp support agents won’t be able to help you troubleshoot issues with your custom code.
If you use a widely unsupported element, you’ll need to segment your list by email client, and design for a specific client. For example, you might use a background image for AOL Mail subscribers, since AOL Mail supports background image CSS.
Email HTML Design Resources for Coders
Whether you’re new to email HTML or you’ve coded plenty of emails before, these resources can help you design templates that look great in a variety of email clients.
Provides resources on design, development methods, code samples, and downloadable email blueprints to help you design and build emails.
Provides step-by-step articles on custom-coded template topics.
Provides campaign style, design, and layout tips in article form.
Provides a summary of the HTML design practices that work best in MailChimp.