About this HTML entity tool
Text typed in the top box is encoded to HTML entities live: the five reserved characters & < > " ' are always escaped, and with the toggle on, non-ASCII characters (Chinese, emoji, symbols) become &#xNNNN; hexadecimal numeric references. The bottom box decodes back in real time, supporting common named entities (40 built in, such as &, <, and ©), decimal &#NNNN; and hexadecimal &#xHHHH; forms.
Unrecognized entities are kept as-is instead of raising an error, so large documents can be cleaned piece by piece. Typical uses: embedding code snippets safely in a page, repairing wrongly-escaped rich text, or inspecting hidden entities inside CMS content. Everything runs locally in your browser — nothing is uploaded.