It’s available for iOS and Android
In essence, emoji are treated by the computer as letters from a non-western language, in much the same way as Japanese and Chinese characters are. But that also means that the software has to explicitly support them – otherwise, it is forced to display a placeholder icon, or even just a blank space (which you might see between the brackets in the paragraph above if your browser doesn’t support emoji).
It also means that each company has to provide its own interpretations of what the emoji descriptions should actually look like – and they don’t always agree. Take the implementations of the “dancer” emoji: for Twitter and Apple, it’s a female flamenco dancer.