Context determines which characters to escape
HTML encoding rules differ by context. In HTML body content, escape &, <, >. Inside a double-quoted attribute value, also escape ". Inside a single-quoted attribute, escape '. Inside a JavaScript string within an HTML attribute (onclick="..."), you need JavaScript escaping as well as HTML escaping. In a CSS value inside a style attribute, yet another encoding layer applies. The tool covers standard HTML content escaping — for complex nested contexts, use a dedicated templating engine.
Encode the ampersand first, always
When applying multiple HTML encodings manually, always replace & with & before replacing any other characters. The other replacements introduce ampersands (< contains an &), so if you encode < first and then encode &, you destroy your already-encoded entities by turning < into <. The tool handles this correctly automatically, but it is important to understand if applying escaping in code.
Use for CMS content that displays code
Technical blog posts and documentation that include code samples often display incorrectly if the code contains < or & characters. CMS editors vary in how they handle escaping — paste your code sample into the entity encoder, copy the escaped version, and paste it into your CMS's HTML mode to ensure it renders correctly. The encoded version displays as the original characters without the browser misinterpreting them as HTML.
Numeric entities for maximum compatibility
Named entities like and © are widely supported but technically require a DTD declaration to be valid. Numeric entities ( and ©) work in all contexts including XML, SVG, and HTML without any DOCTYPE requirement. For maximum cross-environment compatibility — especially in email templates and RSS feeds — prefer numeric entities for any character outside the basic ASCII set.