The HTML Content Block lets you insert your own custom HTML designs in both the email composer and the landing page composer. It works like any other content block but is intended for users comfortable writing HTML, as custom code can affect layout, responsiveness, and rendering across devices, browsers, and email clients.
The block works the same way in both composers, but your HTML is handled differently depending on whether you're designing an email or a landing page. See How Your HTML Is Handled for details.
Quick Reference (Advanced Users)
- Insert: Drag the HTML block into your layout.
- Edit: Replace placeholder code directly or use the EXPAND editor.
-
Emails:
<script>and<iframe>tags are removed; a sanitizer enforces safe HTML. -
Landing pages: HTML is published exactly as entered, including
<script>and<iframe>tags. Test before publishing. - Use cases: Live content, vendor embeds, special formatting, anchor links.
- Visibility: Supports hide on mobile/desktop.
Try it like this: Insert a countdown timer or product recommendation snippet from a third-party provider by pasting their embed code into the HTML block.
Why Use HTML?
Custom HTML is useful when you want to go beyond the standard composer features. Examples include:
- Customized styling: Perfect for fine-tuned formatting beyond block settings.
- Special elements: Insert HTML5 videos or anchor links.
- Advanced CSS effects: Subtle enhancements for landing pages (email client support varies).
- Live content: Add countdowns, product feeds, or other real-time elements using vendor code.
How to Add HTML
-
Insert the block: Drag the HTML Content Block into your design.
- Edit the code: Select the block to open the HTML editor in the sidebar. Replace the placeholder code with your own. Syntax highlighting and indentation assist with readability. Click EXPAND to work in a larger editing window.
How Your HTML Is Handled
How your code is treated depends on which composer you're using.
In Emails
When you add custom code to an email, a built-in sanitizer checks your HTML and removes unsupported or unsafe elements. Tags like <script> and <iframe> are stripped to prevent security, rendering, and deliverability issues.
Allowed HTML Tags:
- Common HTML tags such as
a,abbr,address,area,b,bdo, etc. - Supported attributes include
style,id,class,data-*,title,href,name,target, etc.
In Landing Pages
The landing page composer doesn't filter or change the HTML you add to this block. Tags such as <script> and <iframe> are kept and will run on the published page.
Because your code is published exactly as entered:
- Only use code from sources you trust, such as your own developers or established vendors.
- Preview the page on desktop and mobile before publishing. Invalid or conflicting code can break the layout or affect other blocks on the page.
- Check that any scripts you add don't interfere with other elements on the page, such as forms.
Formatting
A Block option is available to hide on mobile or desktop, allowing you to tailor advanced HTML for specific devices.
Related to