How to login to message app with different Apple IDs I have several Apple IDs, so how can I login with all of these Apple IDs to iMessage on my iMac at once?

I want to send imessage from many apple ID simultaneously. By message app, I sign in my apple ID and I can use imessage. 

But, if I try another apple ID, the previous apple ID will be unavailable.

Is it possible to have multiple Apple ID active at the same time?
Sorry, it appears that you cannot be logged into multiple accounts at once. You can use more than one with iMessage, but you will have to switch between them manually every time you want to use a different Apple ID. Here are a couple of questions that may help:

Multiple Apple ID in Messages.app

How to chat with multiple Apple ID's?