Why use Custom HTML?
The flexibility of the Email Builder means you can achieve the vast majority of layouts without writing any custom code. But if you do have a particularly bespoke element that you want to use in an email you can add HTML as a content section in the builder.
We would recommend using the structure blocks to create your layout in most cases within the Email Builder. The cases where you might want to use custom HTML should be used cautiously and fit within the layout of the builder. A small mistake could negatively impact the layout of your entire email, so proceed with caution.
Examples of custom HTML:
Add 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.).
Add advanced effects with CSS
Get creative with animations! Animation effects are not widely supported by the email clients, but managed correctly they can help drive engagement.
Add live content from external providers
Product recommendations, dynamic ads, personalized maps, countdowns… all of this advanced content can be made possible with the right custom HTML.
How to Add Custom HTML to the Email Builder:
To add your code just drag an HTML content element into your message. It can be positioned alone, with other HTML content items, or mixed with other types of content:
Once you have inserted the HTML content element into your email, click on it. You will see a box appear in the right nav menu in which you can enter your code.
HTML tags allowed in the Email Builder:
The HTML content will automatically correct some 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 major part of email clients, can cause deliverability problems or security risks for the editor an the applications that runs 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
area: alt, coords, href, shape, target
Gmail will automatically strip any CSS that isn't in the email head, meaning any CSS that's added in a html block won't be supported.
Enjoy using custom HTML with care and make sure you test thoroughly across different email clients.