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Deliverability
July 26, 2026
⏱️ 4 min read (687 words)

Summer Deliverability Prep: A Comparative Guide to Email Rendering Methods

email deliverabilitysummer prep guiderenderopsholiday emails
R

Alex Vance & Deliverability Lab Team

Verified across 45 physical email clients & Word MSO rendering engines

# The Competing Approaches When it comes to ensuring your holiday emails render correctly across various clients, there are several approaches you can take. Three popular methods are using a layout transpiler like Retrofit Layout Transpiler, manually writing nested tables, or using a markup compiler like MJML to HTML Compiler. In this article, we'll explore each method in detail, discuss their limitations, and provide a comparison table to help you decide which one to use.

Retrofit Layout Transpiler in Detail The **Retrofit Layout Transpiler** is a tool that automatically converts modern flexbox styles and margins into nested table columns for Outlook desktop clients. This approach is useful because it saves you time and effort in manually writing compatible code for multiple email clients. For example, you can write your email template using flexbox, and then use the transpiler to convert it into a format that Outlook can render correctly.

HTML CODE SNIPPET
<!-- Example flexbox code -->
<div style='display: flex; flex-direction: row;'>
  <div style='width: 50%;'>Column 1</div>
  <div style='width: 50%;'>Column 2</div>
</div>

The Retrofit Layout Transpiler would convert this code into the following nested table structure:

HTML CODE SNIPPET
<!-- Converted nested table code -->
<table>
  <tr>
    <td style='width: 50%;'>Column 1</td>
    <td style='width: 50%;'>Column 2</td>
  </tr>
</table>

However, this approach has its limitations. For instance, the transpiler may not always produce perfect results, and you may need to manually tweak the converted code to get it just right.

Manual Nested Tables in Detail Manually writing nested tables is another approach to ensuring your email templates render correctly across multiple clients. This method gives you complete control over the layout and design of your emails, but it can be time-consuming and prone to errors.

HTML CODE SNIPPET
<!-- Example manual nested table code -->
<table>
  <tr>
    <td>
      <table>
        <tr>
          <td>Column 1</td>
          <td>Column 2</td>
        </tr>
      </table>
    </td>
  </tr>
</table>

While this approach provides the most control, it's also the most error-prone. A single mistake in the table structure can cause rendering issues in certain email clients.

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MJML to HTML Compiler in Detail The **MJML to HTML Compiler** is a markup compiler that takes responsive flex-style layouts and converts them into production-ready nested tables compatible with Outlook. This approach is similar to using a layout transpiler, but it provides more control over the conversion process.

HTML CODE SNIPPET
<!-- Example MJML code -->
<mj-section>
  <mj-column>
    <mj-text>Column 1</mj-text>
  </mj-column>
  <mj-column>
    <mj-text>Column 2</mj-text>
  </mj-column>
</mj-section>

The MJML to HTML Compiler would convert this code into the following nested table structure:

HTML CODE SNIPPET
<!-- Converted nested table code -->
<table>
  <tr>
    <td style='width: 50%;'>Column 1</td>
    <td style='width: 50%;'>Column 2</td>
  </tr>
</table>

Client Compatibility Matrix Table The following table compares the three methods across different email clients:

| Criteria | Retrofit Layout Transpiler | Manual Nested Tables | MJML to HTML Compiler | | --- | --- | --- | --- | | Outlook Compatibility | Excellent | Excellent | Excellent | | Gmail Compatibility | Good | Good | Good | | Yahoo Compatibility | Good | Good | Good | | Flexbox Support | Excellent | Poor | Excellent | | Control Over Layout | Good | Excellent | Good | | Error-Prone | Low | High | Low | | Time-Consuming | Low | High | Low |

By using the right approach to email rendering, you can ensure that your holiday emails render correctly across multiple clients, increasing the chances of your campaigns being successful. With the Retrofit Layout Transpiler and MJML to HTML Compiler tools from RenderOps, you can simplify the process of creating compatible email templates and focus on what matters most – creating engaging content for your audience.

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