A simple way to get Whatsapp messages into vMix is to install the Whatsapp Windows Client. This client mirrors the messages of a cell phone on the Windows desktop. With vMix clipboard copy (PC only) you can get the Whatsapp messages that you have marked with the mouse and copied to the clipboard with CTRL-C. The program runs on every PC in the same network where vMix is running.

You can copy text from any application as long as the text can be marked.

The fade-in/out can also be done by vMix clipboard copy. (Title IN/Title OUT)
A vMix title example is included.

Title filename (whatsapp.gtzip) and text field(TEXT.Text) cannot be changed in the software.
vMix clipboard copy download here

Since my small programs are not digitally signed, this warning appears the first time you start them.