How to send post and create reaction at the same time using API


I could not find info on this. If anyone knows how, please kindly teach me!

I want to be able to post a message and create reaction to the same message together using rest API.

I’m trying to use this in WPF c#. Currently trying with HTTPClient().

I am able to send the message correctly using the incoming webhook. I need a way to get the post id of the message posted in order to add the reactions? Any ideas?