Nombre	phpWebSite	Units	Languages	Mobile Optimization	Dark Mode	AI Features	API Integration	Category Variety
Unit conversion
UltraConverter	ultraconverter.org		32	✅ Yes	✅ Yes	✅ Smart UI + AI SEO	✅ Planned	✅ All (Length, Area…)
UnitConverters	unitconverters.net		❌ No	✅ Yes	❌ No	❌ None	❌ No	✅ Partial
RapidTables			2	❌ No	❌ No	❌ No	❌ No	❌ Limited