I am trying to post message to any channel in a slack team.
My webhook has been properly created and installed into my test team. As part of the install process, I s
The app needs the chat:write:bot
permission to post messages to other channels.
The permission can be added in Manage Apps → your app → OAuth & Permissions:
Reading Slack's own documentation, this was not obvious to me. (although it is mentioned under "Using the Web API" in the Intro to Messaging.)
I created an incoming Webhook, and I found this documentation (see image)
I followed the instructions given in that, and I found that it worked. I can send a message to a different channel than the one the Incoming Webhook was set for