HTMLemails

HTML emails are messages delivered in HTML format, allowing the inclusion of styled text, images, and layout elements to create visually rich content. They are used for newsletters, marketing campaigns, transactional notifications, and other communications where simple plain-text emails would be insufficient. HTML emails rely on a subset of HTML and CSS that varies in support across email clients, which shapes how they are designed and rendered.

Design and development practices for HTML emails emphasize compatibility and predictability. Inline CSS is commonly used because many clients strip or ignore embedded or external styles. Layouts often rely on HTML tables for consistent rendering, with fixed or fluid widths and fallbacks for older clients. Images are typically hosted externally and referenced by URLs, with alt text provided for accessibility. Since many clients block images by default, meaningful alt attributes and a plain-text alternative are important for readability.

Delivery considerations include deliverability and user experience. Proper sender authentication (DKIM, SPF, DMARC), a clean mailing list, and careful content reduce the likelihood of triggering spam filters. Tracking is usually implemented with pixels or URL parameters, but image and pixel blocking by users can limit measurement accuracy. Responsive design is common, using media queries and mobile-friendly layouts, though support for CSS in mobile clients is uneven and requires testing.

Accessibility and standards emphasize providing a plain-text version, ensuring sufficient color contrast, and using semantic structure for assistive technologies. HTML emails should avoid heavy scripts and rely on accessible links and forms where applicable. Because rendering varies by client, ongoing testing across major platforms (Gmail, Outlook, Apple Mail, Yahoo Mail) is essential to ensure consistent presentation.