HTML Email
An email formatted with HTML code that allows rich visual design including images, colors, and formatted text.
Definition
An HTML email uses Hypertext Markup Language to create visually designed messages with formatting, images, links, colors, and layouts beyond what plain text allows. Unlike web pages, HTML emails require specialized coding techniques due to limited CSS support in email clients. Most marketing emails are HTML emails.
Why It Matters
HTML emails enable branded, visually engaging messages that can include images, buttons, and designed layouts. They look professional and can be much more compelling than plain text. However, they require careful coding to display correctly across different email clients.
How It Works
HTML emails use HTML markup and inline CSS styling to create designs. Due to email client limitations, they often use table-based layouts and inline styles rather than modern CSS. The HTML is sent along with a plain text alternative (multipart) for clients that do not render HTML.
Best Practices
- 1Use table-based layouts for consistent rendering across clients
- 2Inline all CSS styles rather than using stylesheets
- 3Always include a plain text version of your email
- 4Test across multiple email clients before sending
HTML Email Structure Table
| Element | Purpose | Email-safe guidance |
|---|---|---|
| Outer container | Sets width and background | Use a predictable max width around 600px |
| Table layout | Keeps columns stable across clients | Prefer table structure for complex layouts |
| Inline styles | Controls typography and spacing | Inline critical CSS instead of relying on stylesheets |
| Plain text part | Provides fallback content | Always send multipart email |
| Image alt text | Explains visuals when images are blocked | Describe the image or action clearly |
HTML Email Compatibility Risks
| Risk | Where it appears | Safer approach |
|---|---|---|
| Modern CSS unsupported | Outlook and older clients | Use inline styles and tested patterns |
| Images blocked by default | Corporate inboxes and privacy-focused clients | Keep the core message readable without images |
| Dark mode changes | Apple Mail, Gmail, Outlook | Test colors and avoid image-only text |
| Mobile clipping | Long layouts or wide designs | Use responsive widths and short sections |
To get a working starting point that already follows these patterns, generate one with the free AI HTML Email Builder and copy the HTML.
HTML vs Plain Text Email
| Format | Best for | Limitation |
|---|---|---|
| HTML email | Brand campaigns, product launches, newsletters | Needs rendering tests and careful coding |
| Plain text email | Personal outreach, simple updates, deliverability-sensitive messages | Limited layout and visual hierarchy |
| Multipart email | Most marketing and transactional sends | Requires maintaining both versions |