I’m trying to build an chrome extension which can be able to send bulk messages in Whatsapp.

I want to follow reverse engineering Whatsapp API method to send bulk messages to specific recipients(using their phone number). Because using Whatsapp Official API or any other third party website, It costs. So I want to build the extension using js/nodejs by following reverse engineering method. How can I execute this process? Is there any other best way to do it?

I’ve already build a chrome extension which retrieves cookies from the user’s browser. Does it help by any means?

The extension will more look like this but has only send text functionality for now