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Uploading Your Custom Email Creatives to cmercury

Get your emails live with ease! Whether you’re uploading a ZIP file or linking to a hosted HTML URL, this guide walks you through everything you need to know to ensure your creatives are uploaded smoothly and render perfectly. Follow the best practices below to avoid common errors and make the most of your custom email designs.

ZIP Upload Requirements

To ensure a smooth and error-free upload, your ZIP file needs to follow specific format and content rules. These include file size limits, folder structure, and the types of files included. Meeting these requirements ensures your HTML email is successfully imported and renders correctly in the editor.

Allowed Format & Size

  • Only .zip files are accepted
  • File size must be 2MB or less

Common Errors:

  • Only ZIP files are allowed.
  • ZIP file size exceeds the 2MB limit.
  • No file uploaded.

ZIP File Structure

  • No nested folders beyond one level
  • No invalid or dangerous file paths

Common Errors:

  • ZIP archive contains invalid or dangerous paths: {filename}
  • ZIP archive contains a subfolder beyond the allowed depth.

Required Files

  • Must contain one and only one HTML file
  • Allowed: .html, .jpg, .jpeg, .png, .gif, .bmp

Common Errors:

  • No HTML file found in the ZIP archive.
  • More than one HTML file found in the ZIP archive.
  • ZIP archive contains invalid files.

HTML File Guidelines

  • Must be extractable by the system
  • Avoid unsupported or non-email-friendly tags

Common Errors:

  • HTML file extraction failed.
  • Your HTML contains tags that are unnecessary in an email template.

Uploading Email Creatives Using a Hosted URL

If you prefer to manage your HTML externally, cmercury allows you to upload your email creatives using a hosted URL.

This method is ideal when your email is already hosted online or generated by an external system. Just paste the direct URL of your HTML file into the provided field — and you’re set.

Hosted URL Upload Guidelines

To ensure smooth uploading and rendering of your HTML email, please follow these rules:

What’s Allowed

  • The URL must directly point to a file with the .html or .htm extension.
  • HTML content must use only:
    • Text
    • Images (served via public URLs)
    • Hyperlinks
    • Inline CSS styles (No external stylesheets)

What’s Not Allowed

  • Forms and Input Fields – These are not supported in email environments and will be stripped or break rendering.
  • External Scripts (JavaScript) – Email clients do not support scripting and it poses a security risk.
  • Interactive Elements – Components like sliders, dropdowns, or dynamic embeds will not function in most email clients.

Tip for Best Results

Before pasting the URL into cmercury, open it in your browser to verify it:

  • Loads properly.
  • Doesn’t redirect.
  • Displays the exact version you want sent.