Best Practices

Emails don’t need to look the same in every email client, but here are few best practices and guidelines to keep in mind to make sure they’re consistently designed and accessible.

General rules and principles

Given Stack Overflow’s reach, we strive to support email clients with low levels of HTML & CSS support (namely Microsoft Outlook, a few versions of Gmail, and a handful of mostly non-US clients). It’s still safest to code emails like it’s 1999.

  • CSS2 instead of CSS3
  • Tables instead of Divs
  • Inline CSS instead of embedded styles or stylesheets
  • HTML text instead of images

Campaign Monitors guide to CSS is the most complete reference for HTML & CSS support in email.

HTML and CSS

  1. Use <table border="0" cellpadding="0" cellspacing="0" role="presentation"> when creating new tables. This negates any unwanted spacing and borders and tells screen readers to skip over the table’s tags and move straight into the content.
  2. When in doubt, nest another table. For finer control of your HTML, try nesting tables when building emails.
  3. Use padding for spacing in table cells. Margins aren’t fully supported on tables and container elements.
  4. Use margin for typography. Margins are fully supported for headline, paragraph, and list tags.
  5. HTML Attributes Most styling is done via CSS. But because some email clients use antiquated rendering engines, they tend to better understand attributes like align, valign, height, and width.
  6. Use align for layout instead of float, grid, or flexbox Floats aren’t supported in Outlook and the others don’t have good support in general.
  7. Define color as #ffffff instead of #fff or rgb(1,2,3). Six-digit hex is supported in inline CSS as well as HTML attributes like bgcolor that are still supported in email.
  8. Don’t forget about preview text. We can specify the text that appears beneath subject lines in many email clients. If preview text is not included, this space will be populated by the email’s content.

Images

  1. Save images as PNG, GIF, or JPG instead of SVG. SVG has almost no support in email, no matter how it’s referenced (inline, Base64, .svg).
  2. Save images as @2x and scale them down using HTML attributes. Since SVG isn’t supported, a 20x20 raster image coded like <img src="40x40-image.png" height="20" width="20"> displays crisply on high-definition screens.

Accessibility

  1. Include role="presentation" on all tables used for layout. This prevents screen readers from reading aloud the structure of each table cell.
  2. Use HTML1 semantic tags whenever possible. Tags like <p> and <h> allow screen readers to quickly jump from section to section.
  3. Include an alt attribute on (almost) every image. Be descriptive and use alt to help readers “see” the email if images aren’t displayed. Use alt="" for images a screen reader should skip (eg. decorative images).
  4. Avoid “Click Here” or “Learn More” link copy. It helps us avoid spam filters and gives context about the link to folks using screen readers or dictation software.
  5. Create a plain text version of every email. It helps us avoid spam filters, some email clients don’t support HTML, and some people just prefer plain text. They also respond better to things like changing font size, family, and color, and work well with screen magnifiers. We don’t have many rules or guidelines for formatting plain text emails, though they typically look something like this.

Testing

Tools to ensure emails look as they should when they’re sent.

Litmus

Litmus allows us to preview screenshots of our emails across 90+ apps and devices. Builder and Checklist are particularly handy for troubleshooting bugs and circulating email code.

Papercut

Papercut allows us to test emails from our code base. Good for making sure templates are built properly, personalized data populates, and email triggers work.