Is there an SDK for in-app chat available?

I’m looking for an in-app chat SDK that works across multiple platforms. Do you have any suggestions?

So far, I’ve tested as below.

Firebase: There is a chat sample, but it appears to be more about syncing data between apps.

any sample codes.

Hi,
I came through a Chat API/SDK which is most useful to integrate across multiple platforms, You can definitely try CONTUS MirrorFly’s free demo.

MirrorFly chat AIP