About This Tool
HTML uses special characters like angle brackets, ampersands, and quotation marks to define tags and structure. If you want to display these characters as actual text on a webpage, such as showing a code snippet in a tutorial, you must convert them into HTML entities. Without this conversion, the browser interprets the characters as markup rather than displaying them as text. Our Free HTML Encoder/Decoder instantly converts raw text into safe HTML entities (like turning angle brackets into their entity equivalents) and back again. The encoder protects against Cross-Site Scripting (XSS) vulnerabilities by ensuring user input is treated as text, not executable code. The decoder reverses the process, converting entities back to readable characters when you need the original text. This is an essential tool for developers sanitizing database inputs, bloggers posting code examples, content managers fixing broken snippets, and security professionals auditing web applications for injection vulnerabilities. Simply paste your text, choose encode or decode, and get the result instantly. Swap mode lets you chain operations, converting back and forth until the output is exactly what you need. Copy the result with one click and paste it into your code, CMS, or database query.
Why Escape HTML?
If you type a script tag directly into an HTML file, the browser tries to run it as code. This leads to broken layouts and major security vulnerabilities known as Cross-Site Scripting (XSS). Escaping converts special characters into their entity equivalents, telling the browser to simply display the text rather than execute it.
Any application that accepts user input and renders it on a web page is potentially vulnerable to XSS if the input is not properly escaped. This includes comment sections, form fields, search boxes, and URL parameters. A single unescaped input field can compromise an entire website and its users.
Common HTML Entities
The five critical characters that must be escaped in HTML and XML contexts:
- < (less than): Encoded as
<- prevents the browser from interpreting text as an opening HTML tag - > (greater than): Encoded as
>- prevents interpretation as a closing tag - & (ampersand): Encoded as
&- prevents interpretation as the start of an entity reference - " (double quote): Encoded as
"- prevents breaking out of HTML attribute values - ' (single quote): Encoded as
'- prevents breaking out of single-quoted attributes
These five characters are sufficient for safe HTML rendering in virtually all contexts. Additional entities exist for special symbols (copyright, trademark, currency), but the Big Five are the security-critical set.
When to Encode vs Decode
Use encoding when you need to safely display user-generated text, code snippets, or any content containing HTML special characters on a web page. Common scenarios include inserting user comments into a page, displaying source code in tutorials, building email templates with dynamic content, and storing text that will later be rendered in HTML.
Use decoding when you receive entity-encoded text and need the original characters. This happens when extracting text from HTML documents for plain-text use, cleaning up over-encoded content from CMS exports, parsing RSS feeds or API responses that encode special characters, and preparing content for non-HTML contexts like CSV files or plain-text emails.
Security Best Practices for HTML Encoding
Proper HTML encoding is the first line of defense against injection attacks, but it should be part of a broader security strategy:
- Encode on output, not input: Store the original text in your database and encode it when rendering to HTML. This preserves the original data and allows you to render it safely in different contexts (HTML, JSON, URL).
- Use context-appropriate encoding: HTML entity encoding protects against XSS in HTML body text and attribute values. URL parameters need URL encoding. JavaScript strings need JavaScript escaping. Each context requires its own encoding method.
- Content Security Policy (CSP): Add CSP headers to your server configuration as a second layer of defense. CSP prevents inline script execution even if an encoding mistake occurs.
- Validate input types: If a field expects a number, reject non-numeric input before it reaches your encoding layer. Validation and encoding work together to create defense in depth.
Frequently Asked Questions
What is XSS and how does encoding prevent it?
Cross-Site Scripting (XSS) is a security vulnerability where attackers inject malicious scripts into webpages viewed by other users. For example, if a comment field does not encode user input, an attacker could submit a script tag that steals cookies or redirects users to a phishing site. Proper HTML escaping converts special characters to entities, ensuring the browser displays the text as-is instead of executing it as code.
Does this tool handle all HTML entities?
The Encoder focuses on the five critical characters for XML and HTML syntax (angle brackets, ampersand, and both quote marks). The Decoder handles virtually any named entity (like copyright symbols) or numeric entity (like decimal and hex character references) supported by modern browsers.
Is double-encoding a problem?
Yes. Double-encoding happens when already-encoded text is encoded again, turning & into &amp;. This causes visible entity codes in your rendered output instead of the intended characters. If your text already contains entities, decode it first, then re-encode once. This tool lets you swap between modes to fix double-encoded content by decoding until the text looks correct.
Can I use this for XML encoding too?
Yes. The five characters encoded by this tool are the same characters that must be escaped in XML documents. XML uses the same entity syntax as HTML for these characters. If you are generating XML, RSS feeds, or SOAP payloads, this encoder produces valid output for those formats as well.