Sending a 200 OK is not enough. It also has to be empty OR contain a list of input validation errors in the correct format as JSON. If your response contains any other text (e.g. a warning message) it will create this error. As it says in the documentation: When the submission is without exception, … Read more
That Slack API endpoint unfortunately appears to be broken in its handling of cross-origin requests from frontend JavaScript code—in that it doesn’t handle the CORS preflight OPTIONS request as it should—so the only solution seems to be to omit the Content-Type header. So it looks like you need to remove the following from the headers … Read more
Bots can use the undocumented API method chat.command to invoke slash commands. See here for an unofficial documentation page of this API method. This question was also answered here.
If I understand your question correctly, you want to send direct messages to users in the app channel instead of the standard slackbot channel. In order to do that you need to Your app needs the bot scope and a bot user Open a direct message channel from your app with the user with conversations.open. … Read more