Working with HTML Content Blocks

The Custom HTML content block allows you to easily add your own HTML to an email message that you are designing with the editor. 

HTML experts only: Using your own code may affect how the message is rendered in email clients, preventing it from adjusting to the screen size (i.e. the "responsiveness" of the message). Be sure to use HTML that is email compliant and responsive.

Why use custom code?

There are many scenarios in which it makes sense to add your own HTML code: 

  • Adding more customized content
    • You are not limited by a set of predefined parameters and can, therefore, have more granular control of the styles applied. 
  • Adding HTML 5 video, anchor links, etc.
    • You can now add content that is not available as a standard content element in the editor (HTML 5 video, anchor links, etc.). 
  • Adding advanced effects with CSS
    • Get creative with animations! Animation effects are not widely supported by the email clients but, when managed correctly, they provide a faster load-time, smaller file sizes, and more interactivity than their GIF counterparts. 
  • Adding live content from external providers
    • Product recommendations, dynamic ads, personalized maps, countdowns… all of this advanced content can now be easily included in a message created with the editor. Just copy and paste the code provided to you by the vendor that you are working with. 

Adding an HTML Block

Drag the HTML content block to the editor from the available content blocks. It can be positioned alone, with other HTML content items, or mixed with other types of content:


The newly inserted content block will show some default placeholder text. Click on it and the right-side property panel will display the HTML code editing pane. You will find some placeholder code inside the editing area.

Paste your own HTML code or write it directly in the editing area. The system will highlight your syntax and indent your code to make it more readable.



Eligible HTML Tags and Attributes

The HTML content will automatically correct issues like HTML tags that are left open, and strip out code that cannot be used, such as script tags or iframe tags (these code tags are not allowed by the majority of email clients, can cause deliverability issues or pose security risks for the editor on the applications that run it). 

Allowed tags list:

a, abbr, acronym, address, area, b, bdo, big, blockquote, button, caption, center, cite, code, colgroup, dd, del, dfn, dir, div, dl, dt, em, fieldset, font, form, h1, h2, h3, h4, h5, h6, i, ins, kbd, label, legend, li, map, menu, ol, optgroup, option, p, pre, q, s, samp, select, small, span, strike, strong, sub, sup, table, tbody, td, textarea, tfoot, th, thead, u, tr, tt, u, ul, var

Allowed attributes list:

general attributes: style, id, class, data-*, title
a: href, name, target
img: align, alt, border height, hspace, src, vspace, width, usemap
table: align, bgcolor, border, cellpadding, cellspacing, width
tbody: align, valign
td: align, bgcolor, colspan, height, rowspan, valign, width
tr: align, bgcolor, valign
tfoot: align, valign
th: align, bicolor, colspan, height, rowspan, valign, width
thead: align, valign
li: type
map: name
area: alt, coords, href, shape, target