I'm completely new to slack development and I might sound crazy here.
This is what I have noticed. Whenever I use my incoming webhook URL to test messages using postman, it works fine. BUT, when I use it in my app and push the code in github (so it deploys to heroku), the incoming webhook gets removed. Is this something expected and that I missed reading in the documentation?
Ok, got answer to this. Basically, got an email from slack explaining the reason.
We recently discovered a publicly accessible incoming webhook associated with the Journey Alert Bot app installed on your sync.slack.com workspace. This can happen when someone who created or has access to a webhook URL posts it on a public site, such as Github or other code-sharing forums. None of your data is at risk — webhooks can only send messages into Slack and cannot access any data.