Copynix

HTML Entity Encoder and Decoder Online β€” Plus Live HTML Preview

Frequently Asked Questions

What are HTML entities?

HTML entities are special codes used to display reserved characters in HTML. For example, '<' is encoded as '&lt;' and '&' as '&amp;'. This prevents browsers from interpreting them as HTML tags.

When do I need to HTML-encode text?

Always encode user-provided text before inserting it into HTML to prevent XSS (Cross-Site Scripting) attacks. For example, if a user enters '<script>', it should become '&lt;script&gt;'.

What is the HTML preview mode?

The HTML preview renders raw HTML in a sandboxed iframe so you can see how it looks in a browser without executing any scripts.

Which characters are HTML-encoded?

The standard HTML entities are: & β†’ &amp;, < β†’ &lt;, > β†’ &gt;, " β†’ &quot;, ' β†’ &#39;. Extended encoding also covers accented characters, copyright symbols, and more.

Which HTML characters must always be escaped to prevent XSS?

At minimum, always escape these five: & (β†’ &amp;), < (β†’ &lt;), > (β†’ &gt;), " (β†’ &quot;), and ' (β†’ &#39;). These prevent XSS and HTML injection when inserting user-provided content into web pages.

What is the difference between named and numeric HTML entities?

Named entities use a descriptive name: &amp; for &, &lt; for <. Numeric entities use the Unicode code point: &#38; for & (decimal) or &#x26; for & (hex). Both are valid; named entities are more readable.

How do HTML entities prevent XSS attacks?

XSS attacks inject malicious scripts via user input. If a user submits '<script>alert(1)</script>', entity-encoding converts it to '&lt;script&gt;alert(1)&lt;/script&gt;' β€” the browser displays it as text instead of executing it as code.

HTML entities are essential for web security. Any user-provided content inserted into HTML must be entity-encoded to prevent Cross-Site Scripting (XSS) β€” one of the most common web vulnerabilities. This tool also lets you preview raw HTML in a safe sandboxed environment.

How to use

  1. 1

    Choose your mode

    Select 'Encode' to convert special characters to HTML entities (< β†’ &lt;). Select 'Decode' to convert entities back to characters. Use 'Preview' to render raw HTML and see how it looks in a browser.

  2. 2

    Paste your input

    For encoding: paste user-provided text or content that needs to be safely embedded in HTML. For decoding: paste HTML-encoded text to make it human-readable. For preview: paste complete HTML markup.

  3. 3

    Read the output

    The encoded, decoded, or rendered result appears instantly. For the preview mode, HTML is rendered in a sandboxed iframe β€” JavaScript is disabled for security.

  4. 4

    Copy and use in your code

    Copy the entity-encoded output and insert it into your HTML templates, email content, or anywhere user content needs to appear safely.

Use cases

  • Prevent XSS vulnerabilities

    Before inserting user input into HTML (in template engines, email generators, or static site builders), entity-encode it here to confirm the encoding is correct. Characters like <, >, &, and " must be encoded to prevent script injection.

  • Debug escaped HTML

    CMS systems, email clients, and databases often store HTML with entities. Decode the text here to see the original content without the encoding noise.

  • Test email HTML

    Email clients have inconsistent HTML support. Use the preview mode to render your email HTML and catch rendering issues before sending β€” without needing to send a test email.

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HTML entity encoding converts reserved HTML characters β€” <, >, &, ", ' β€” into their equivalent entity references (&lt;, &gt;, &amp;, &quot;, &#39;). This is essential for safely rendering user-supplied content in an HTML page. Inserting unescaped user input directly into HTML is the root cause of Cross-Site Scripting (XSS) attacks, one of the most common web security vulnerabilities.

Use this tool when you need to safely display code snippets, user-generated text, or API response data inside an HTML template, or when you want to understand what entity sequences a browser is actually receiving from a server. The decoder direction is equally useful when parsing HTML content and extracting the original text from entity-encoded strings.