` executes as code. With encoding: `<script>alert(\"XSS\")</script>` displays as text. Attack vectors: form inputs, URL parameters, cookies, database content. Defense layers: (1) Encode output (HTML entities), (2) Validate input (whitelist), (3) Content Security Policy headers, (4) HttpOnly cookies. Encoding alone not sufficient: use comprehensive XSS prevention, sanitize HTML if allowing markup, use frameworks that auto-encode (React, Vue). This tool helps encode untrusted content before rendering."}},{"@type":"Question","name":"What is the difference between HTML encoding and URL encoding?","acceptedAnswer":{"@type":"Answer","text":"HTML encoding: for HTML content, encodes `<>&\"'` to entities, used in HTML body/attributes, prevents HTML interpretation. URL encoding (percent encoding): for URLs, encodes space as `%20` or `+`, special chars as `%XX` hex, used in query strings/paths, prevents URL parsing issues. Different contexts need different encoding: HTML entity: `<` for `<`, URL encoding: `%3C` for `<`. Don't mix: URL-encoded in HTML looks wrong (`%20` displays as `%20`). When to use: HTML encoding in page content, URL encoding in hrefs/src attributes, both in JavaScript strings. This tool does HTML entity encoding; use separate tool for URL encoding."}},{"@type":"Question","name":"Which characters must be encoded in HTML attributes?","acceptedAnswer":{"@type":"Answer","text":"Required in attribute values: `\"` (double quote) → `"` if using double-quoted attributes, `'` (single quote) → `'` if using single-quoted attributes, `<` → `<` (less common but safe), `&` → `&` (always). Example: `
`. Attribute context matters: URL attributes (href, src): also URL-encode, JavaScript attributes (onclick): use JSON.stringify, data attributes: HTML encode, style attributes: CSS encode. Best practice: always use quotes around attributes, use double quotes with " encoding, encode & in all attributes. This tool encodes for safe attribute insertion."}},{"@type":"Question","name":"How do I handle international characters and Unicode in HTML?","acceptedAnswer":{"@type":"Answer","text":"Unicode characters can be: (1) Used directly if UTF-8 charset: ``, no encoding needed. (2) HTML entities: `é` for é (named), `é` for é (decimal), `é` for é (hex). Modern approach: use UTF-8 directly, it's simpler and more readable. Encode entities only for: HTML special chars (`<>&\"`), control characters, invisible chars, compatibility with non-UTF-8 systems. Emoji: use directly in UTF-8 or numeric entities `😀` 😀. Right-to-left text: use proper HTML markup (`dir=\"rtl\"`), not entities. This tool preserves Unicode by default, encodes only HTML special characters."}},{"@type":"Question","name":"What is the difference between encoding and sanitizing HTML?","acceptedAnswer":{"@type":"Answer","text":"Encoding: converts special chars to entities, displays everything as text, no HTML tags work, safest for untrusted content, example: `` → `<b>`. Sanitizing: allows some HTML, removes dangerous tags/attributes, permits formatting (``, ``, `

`), blocks scripts (``, `\" onclick=\"alert(1)\"`. This tool helps test encoding correctness before deploying."}}]}

Home/Tools/HTML Entity Encoder/Decoder

HTML Entity Encoder/Decoder

Encode and decode HTML entities and special characters. Prevent XSS attacks by converting characters to HTML-safe entities for web security.

Statistics

0
Input Chars
0
Output Chars
0
Total Entities
0
Named
0
Decimal
0
Hex
0.00x
Ratio

Quick Examples

Need Professional IT Services?

Our IT professionals can help optimize your infrastructure and improve your operations.

Get Free ConsultationView Services

References & Citations

  1. W3C. (2024). HTML5 Character References. Retrieved from https://dev.w3.org/html5/html-author/charref (accessed January 2025)
  2. OWASP. (2024). OWASP XSS Prevention Cheat Sheet. Retrieved from https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html (accessed January 2025)

Note: These citations are provided for informational and educational purposes. Always verify information with the original sources and consult with qualified professionals for specific advice related to your situation.

Key Security Terms

Understand the essential concepts behind this tool

Base64 Encoding

A binary-to-text encoding scheme that converts binary data into ASCII characters for safe transmission over text-based protocols.

Learn more →

URL Encoding (Percent Encoding)

A mechanism for encoding special characters in URLs using percent signs followed by hexadecimal values.

Learn more →

SQL Injection

A web security vulnerability allowing attackers to interfere with database queries through unsanitized input.

Learn more →

Markdown

A lightweight markup language that uses plain text formatting to create structured documents.

Learn more →
View all terms in our glossary →
` executes as code. With encoding: `<script>alert(\"XSS\")</script>` displays as text. Attack vectors: form inputs, URL parameters, cookies, database content. Defense layers: (1) Encode output (HTML entities), (2) Validate input (whitelist), (3) Content Security Policy headers, (4) HttpOnly cookies. Encoding alone not sufficient: use comprehensive XSS prevention, sanitize HTML if allowing markup, use frameworks that auto-encode (React, Vue). This tool helps encode untrusted content before rendering."}},{"@type":"Question","name":"What is the difference between HTML encoding and URL encoding?","acceptedAnswer":{"@type":"Answer","text":"HTML encoding: for HTML content, encodes `<>&\"'` to entities, used in HTML body/attributes, prevents HTML interpretation. URL encoding (percent encoding): for URLs, encodes space as `%20` or `+`, special chars as `%XX` hex, used in query strings/paths, prevents URL parsing issues. Different contexts need different encoding: HTML entity: `<` for `<`, URL encoding: `%3C` for `<`. Don't mix: URL-encoded in HTML looks wrong (`%20` displays as `%20`). When to use: HTML encoding in page content, URL encoding in hrefs/src attributes, both in JavaScript strings. This tool does HTML entity encoding; use separate tool for URL encoding."}},{"@type":"Question","name":"Which characters must be encoded in HTML attributes?","acceptedAnswer":{"@type":"Answer","text":"Required in attribute values: `\"` (double quote) → `"` if using double-quoted attributes, `'` (single quote) → `'` if using single-quoted attributes, `<` → `<` (less common but safe), `&` → `&` (always). Example: `
`. Attribute context matters: URL attributes (href, src): also URL-encode, JavaScript attributes (onclick): use JSON.stringify, data attributes: HTML encode, style attributes: CSS encode. Best practice: always use quotes around attributes, use double quotes with " encoding, encode & in all attributes. This tool encodes for safe attribute insertion."}},{"@type":"Question","name":"How do I handle international characters and Unicode in HTML?","acceptedAnswer":{"@type":"Answer","text":"Unicode characters can be: (1) Used directly if UTF-8 charset: ``, no encoding needed. (2) HTML entities: `é` for é (named), `é` for é (decimal), `é` for é (hex). Modern approach: use UTF-8 directly, it's simpler and more readable. Encode entities only for: HTML special chars (`<>&\"`), control characters, invisible chars, compatibility with non-UTF-8 systems. Emoji: use directly in UTF-8 or numeric entities `😀` 😀. Right-to-left text: use proper HTML markup (`dir=\"rtl\"`), not entities. This tool preserves Unicode by default, encodes only HTML special characters."}},{"@type":"Question","name":"What is the difference between encoding and sanitizing HTML?","acceptedAnswer":{"@type":"Answer","text":"Encoding: converts special chars to entities, displays everything as text, no HTML tags work, safest for untrusted content, example: `` → `<b>`. Sanitizing: allows some HTML, removes dangerous tags/attributes, permits formatting (``, ``, `

`), blocks scripts (``, `\" onclick=\"alert(1)\"`. This tool helps test encoding correctness before deploying."}}]}

Frequently Asked Questions

Common questions about the HTML Entity Encoder/Decoder

HTML entities encode special characters that have meaning in HTML: < becomes &lt;, > becomes &gt;, & becomes &amp;, " becomes &quot;, ' becomes &#39; or &apos;. Why important: prevents breaking HTML structure, avoids XSS (cross-site scripting) attacks, displays reserved characters literally, ensures proper rendering. Example: displaying code <script> without executing it. Two formats: named entities (&nbsp;), numeric entities (&#160; decimal, &#xA0; hex). Always encode user input before displaying in HTML to prevent security vulnerabilities.

Read More

⚠️ Security Notice

This tool is provided for educational and authorized security testing purposes only. Always ensure you have proper authorization before testing any systems or networks you do not own. Unauthorized access or security testing may be illegal in your jurisdiction. All processing happens client-side in your browser - no data is sent to our servers.