HTML Entity Encode / Decode — Free Online Tool

HTML Entity Encode / Decode: free online tool with examples and documentation. Convert, generate, format, or analyze data instantly in your browser.

Use this free online HTML Entity Encode / Decode directly in your browser. No signup required, no data leaves your device. Part of Utilier — a collection of 133+ developer utilities.

What is HTML Entity Encode / Decode?

Converts special characters to HTML entities (& → &, < → <) and back. It ensures reserved markup characters display as text instead of being interpreted by the browser. HTML entities are an output-encoding mechanism for a specific HTML context: text nodes and quoted attributes have different requirements, while URLs and JavaScript strings need their own encodings. Correct encoding is a core defense when rendering untrusted data.

HTML entities are textual escape sequences that let a document represent reserved markup characters literally. For example, a browser reads < as visible text instead of the start of a tag. Encoding is context-sensitive: values placed in element text and quoted attributes need escaping, while JavaScript and URLs require their own encodings.

Why use html entities?

Displaying user-generated content in HTML without encoding is a security vulnerability (XSS). HTML encoding ensures < > & " ' are rendered as text, not interpreted as HTML/JS.

When to use html entities

Use when displaying user input in web pages, building HTML strings in code, fixing broken encoded text, or preparing content for safe inclusion in HTML attributes.

How to use html entities

Simple steps to use this tool effectively.

Enter input: Paste or type your input data into the input area. Supports various formats and encodings.
Configure options: Select format, encoding, or other options as needed. Sensible defaults are provided for quick start.
Process data: Click the convert, generate, or format button. Many tools show real-time results as you type.
Review output: Check the output for correctness. Validation errors are shown if any issues are detected.
Copy or export: Click copy button to clipboard or download results as a file for use in your project.
Try examples: Use provided examples to understand features and learn common patterns and use cases.

Key features

Fast processing: Quick and accurate html entities operations with instant results.
Input validation: Validates input format and provides helpful error messages and suggestions for fixes.
Multiple formats: Supports various input and output formats for maximum compatibility and flexibility.
Built-in examples: Includes common use case examples to help you get started quickly and learn.
Copy & export: Easy copying to clipboard or downloading results as files for use in projects.
Real-time updates: See results instantly as you type or change options. No need to click buttons.
Client-side privacy: All processing happens in your browser. No data is uploaded to servers or stored.
Comprehensive docs: Detailed documentation, specifications, FAQs, and troubleshooting help included.

Common use cases

Web development: Use html entities during coding, debugging, and testing web applications.
API integration: Test API requests and responses, validate data formats, debug integration issues.
Data conversion: Convert between different data formats, encodings, or representations as needed.
Learning & education: Understand concepts through interactive examples, experimentation, and documentation.
Documentation: Create clear examples and code samples for technical documentation and guides.
Troubleshooting: Debug issues in development or production by validating, converting, or analyzing data.
Quick prototyping: Rapidly test ideas, generate sample data, or validate approaches without writing code.

Examples

Encode and decode HTML entities.

Basic encoding

<script>alert('xss')</script>

&lt;script&gt;alert(&#39;xss&#39;)&lt;/script&gt;

Ampersand in URLs

page?a=1&b=2

page?a=1&amp;b=2

Technical reference

HTML Entity Encode / Decode specifications, standards, and technical details.

Standards compliance: Follows industry standards, specifications, and best practices for compatibility and correctness.
Input formats: Supports common input formats used in web development, APIs, and data interchange.
Output formats: Provides multiple output format options for different use cases and requirements.
Character encoding: Handles UTF-8 and other character encodings correctly for international text support.
Browser support: Works in all modern browsers: Chrome, Firefox, Safari, Edge. Requires JavaScript enabled.
Performance: Optimized for fast processing of typical workloads. Large inputs may take longer depending on device.
Security & privacy: Client-side processing only. No data is uploaded to servers, stored, or transmitted externally.
Accuracy: Validated against test suites, specifications, and real-world examples to ensure correctness.
Limitations: Handles typical use cases efficiently. Extremely large inputs (megabytes) may be slower or hit browser limits.
Updates: Regularly updated with new features, improvements, bug fixes, and user-requested enhancements.

Common mistakes to avoid

Double encoding

Encoding already-encoded text produces &amp; instead of &. Check if text is already encoded before processing.

Missing attribute encoding

Inside HTML attributes, also encode quotes: " → " and ' → '. This prevents attribute injection attacks.

Frequently asked questions

What's the difference between HTML encoding and URL encoding?

HTML encoding uses named/numeric entities (&, <) for safe display IN HTML. URL encoding uses %XX for safe use IN URLs. Different contexts, different encoding.

Should I encode all content?

Yes — any dynamic content rendered in HTML should be encoded. Use your framework's auto-escaping (React, Vue, Angular all do this by default) rather than manual encoding.

References

Privacy and availability

Runs entirely in your browser — zero server processing
No signup or account required
Works offline once loaded
Fast, lightweight, no external dependencies
Available as a browser extension for Chrome and Firefox

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