I was setting the password on a website which does not support 2FA.
So I tried adding an Unicode emoji to the password and it was accepted and functional on that website.
But when I launched the Bitwarden app (v2.12.0) on my iPhone and tried to open the entry with an emoji in the password, the app crashed.
If I delete the emoji from the password on https://vault.bitwarden.com/, I can open the entry.
I know it is not a regular use case but If there are websites accepting emoji in the password, it should be fixed.
Since Bitwarden is designed to be used by multiple clients and browsers on multiple operating systems, I don’t know that this is feasible yet. Different operating systems don’t always represent emojis the same way, so what might work on your iPhone or Mac might not work on Android or Windows. That’s not Bitwarden’s fault, obviously, but it would make it difficult or impossible to implement such a feature, IMO.
One thing you might try is ‘peppering’ your stored passwords with emojis at the end - that is, allow Bitwarden to store and fill the regular part of your password, and then you type in one or a few emojis manually at the end in the password box. This is actually a very secure way to use passwords since even if someone obtains your Bitwarden data, they won’t know your emoji ‘pepper’. But of course, this will only work if the site you login to accepts your inputted emojis on all the different devices you might use.