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Email CSS Inliner Inline CSS styles into HTML elements for email template compatibility.

Email CSS Inliner illustration
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Email CSS Inliner

Inline CSS styles into HTML elements for email template compatibility.

1

Paste your HTML

Enter the HTML markup for your email template.

2

Paste your CSS

Enter the CSS styles that should be applied inline.

3

Copy inlined HTML

Preview the result and copy the HTML with all styles inlined.

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What Is Email CSS Inliner?

The Email CSS Inliner converts external CSS rules into inline style attributes on HTML elements, making your email templates compatible with major email clients. Most email clients (Gmail, Outlook, Yahoo Mail) strip <style> tags and ignore external stylesheets, requiring CSS to be inlined on each element. This tool takes your HTML markup and CSS rules, matches selectors to elements, and inserts the corresponding style declarations directly on each element. It handles tag selectors and class selectors, making the conversion process quick and automated. The preview shows the styled output so you can verify the result before copying.

Why Use Email CSS Inliner?

  • Automatic conversion of CSS rules to inline style attributes
  • Handles both tag and class CSS selectors
  • Live preview of the styled HTML output
  • Essential for email client compatibility (Gmail, Outlook, Yahoo)

Common Use Cases

Email Template Development

Inline styles for marketing and transactional email templates.

Newsletter Design

Prepare newsletter HTML with inline styles for broad client support.

Automated Emails

Process CSS for automated notification and welcome email templates.

Email Testing

Convert and test email HTML across different email clients.

Technical Guide

Email HTML has significant CSS limitations compared to web HTML. Most email clients support only inline styles (via style attributes), basic CSS properties, and table-based layouts. Gmail strips <style> tags in the <head>. Outlook uses the Word rendering engine with limited CSS support. The inlining process parses CSS rules, matches selectors to HTML elements, and adds matching declarations as style attributes. Simple tag selectors (h1, p, a) and class selectors (.button, .container) are the most reliably matched. Complex selectors (combinators, pseudo-classes, pseudo-elements) have limited support in email clients anyway. After inlining, test with tools like Litmus or Email on Acid across multiple clients. Keep email HTML simple: use tables for layout, inline styles for all appearance, and include both HTML and plain-text versions. Avoid CSS features like flexbox, grid, position, and float in emails.

Tips & Best Practices

  • 1
    Use table-based layouts for maximum email client compatibility
  • 2
    Test inlined HTML across Gmail, Outlook, and Apple Mail at minimum
  • 3
    Keep CSS simple—avoid selectors that cannot be inlined (pseudo-elements)
  • 4
    Include width attributes on tables and images for Outlook compatibility

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Frequently Asked Questions

Q Why do emails need inline CSS?
Most email clients strip <style> tags and ignore external stylesheets, only supporting CSS in style attributes.
Q Does this tool handle all CSS selectors?
It handles tag selectors and class selectors. Complex selectors (pseudo-classes, combinators) have limited email support anyway.
Q Which email clients require inline CSS?
Gmail, Yahoo Mail, Outlook, and many others. Only a few modern clients support <style> tags.
Q Can I use flexbox or grid in emails?
No, most email clients do not support modern CSS layout. Use table-based layouts for emails.
Q Should I test the inlined HTML?
Absolutely. Always test in multiple email clients. Use services like Litmus or Email on Acid for cross-client testing.

About This Tool

Email CSS Inliner is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.