Unlocking Creative Freedom with the HTML Block in Salesforce Marketing Cloud

sfmcstories
Aug 17
3 min read

In email marketing, drag-and-drop editors offer convenience—but for full creative control, nothing beats the HTML block. Whether you're crafting advanced layouts, dynamic personalization, or ensuring pixel-perfect branding, the HTML block gives you freedom and flexibility. *HTML: HyperText Markup Language

What Is the HTML Block?

The HTML block in SFMC’s(Marketing Cloud Engagement) Content Builder lets you insert your own HTML code directly into your email. Pair it with AMPscript and personalization strings to craft intelligent, tailored, and visually compelling emails.

HTML Block in Salesforce Marketing Cloud Engagement

Why It Pays to Use It

Full Creative Control: Break away from template constraints and customize every element.
Advanced Personalization: Seamlessly embed data-driven content using AMPscript and personalization strings.
Brand Integrity: Achieve consistent, pixel-perfect design across communications.
Enhanced Interactivity: From countdown timers to custom animations—go beyond what standard blocks allow.

How to Create an HTML Block in SFMC?

Here are the detailed steps to create and use an HTML block:

Navigate to Content Builder: From your Salesforce Marketing Cloud dashboard, open Content Builder.
Create New Content: Click on Create and choose Content Block.
Select HTML Block: From the available block types, select HTML.
Navigating to HTML Block
Enter a Name & Folder Location: Give your block a clear, descriptive name and save it in the appropriate folder for easy management.
Add Your HTML Code: A code editor will appear. Paste or write your custom HTML here. You can include inline CSS, AMPscript, and personalization strings as needed.
Preview & Test: Use the preview option to check how the HTML renders across devices. Send test emails to verify functionality.
Save & Reuse: Save the block for use in multiple campaigns, ensuring consistency and efficiency.
Steps to create HTML Block

Salesforce’s Guidance: Use Code Snippets

According to the Salesforce Help article “Add HTML Content,” using code snippets is highly recommended. They help preserve your custom markup and avoid unintentional wrappers or alterations when the email is processed(Email on Acid). Embed reusable elements like headers, disclaimers, and tracking scripts cleanly using the “Insert Code Snippet” tool.

Email on Acid: Best Practices for HTML Email Development

Here are key practices from Email on Acid’s "HTML Email Development Best Practices" blog that complement your SFMC HTML block strategy(Email on Acid):

1. Set a Proper DOCTYPE

Always include:

<!DOCTYPE html>

This ensures rendering is not forced into quirks mode.

2. Use Correct <html> Tag with Accessibility and Outlook Support

<html lang="en" xmlns="https://www.w3.org/1999/xhtml"
      xmlns:v="urn:schemas-microsoft-com:vml"
      xmlns:o="urn:schemas-microsoft-com:office:office">

Add lang="en" for accessibility. The VML namespace ensures compatibility with Microsoft Outlook for enhanced control.

3. Layout with Tables

Tables remain the most reliable structure given inconsistent CSS support across email clients(Email on Acid, Wikipedia). Use inline padding and table-based layouts to ensure consistent rendering.

4. Incorporate Font Stacks & Web Fonts Thoughtfully

Use font stacks and fallback fonts to ensure consistent text appearance when custom fonts aren’t supported.

Combined Workflow: HTML Block + Best Practices

Before You Code

Decide where the HTML block adds value (e.g., custom header, interactive sections).
Use code snippets for modular components.

Development Checklist

Step	Action
1	Include proper DOCTYPE and <html> tag with attributes.
2	Build layout using tables; avoid complex CSS reliance.
3	Use inline CSS for styling and ensure fonts degrade gracefully.
4	Integrate personalization using AMPscript/personalization strings.
5	Wrap reusable components in snippets for consistency and ease.

Testing & Review

Preview emails across clients—especially Outlook and mobile.
SFMC's HTML block paired with code snippets helps keep your code clean.
Optionally, use platforms like Email on Acid or Litmus to test across 100+ email clients and preview dark mode variations, accessibility, and deliverability(Martech Zone, Email on Acid, Wikipedia).

Summary

The HTML block in Salesforce Marketing Cloud is your gateway to creativity and precision. Back it with code snippets to maintain structure, and embrace proven best practices from Email on Acid—like DOCTYPE setup, table layouts, and font fallback strategies—for reliable cross-client rendering. Top it all off with thorough testing to ensure flawless execution.