Send a Slack message

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

The ID of the Slack channel to post the message to (e.g. C0123456), or the ID of a Slack user to send a DM to (e.g. U0123456). If posting to a channel, the Tightknit app must be a member or have access to join the channel, and the Tightknit app must have permission to post to the channel.

The text content of the message. It can be formatted as plain text or with Slack markdown. The text field is also used for Slack notifications and by screen readers when reading Slack messages.

The timestamp of a Slack message to reply to. Only relevant when sending a message to a thread. Avoid using a reply's ts value; use its parent's ts instead. If a parent message matching the ts is not found, Slack will post the message to the channel instead of the thread.