The best way to Unmimiify HTML online is by b using the fixcode.org HTML UnMinifier
Fixcode.org also has the following minifiers
- CSS UnMinifier: https://fixcode.org/beautify/css
- javaScript UnMinifier:https://fixcode.org/beautify/js
- JSON UnMinifier: https://fixcode.org/beautify/json
- XML UnMinifier: https://fixcode.org/beautify/xml