Slack Trigger

Type ID: slackTrigger  ·  Kind: Trigger  ·  Trigger style: poll  ·  Ports: 1 in, 1 out (0 in when used as the workflow's root trigger)

Polls the Slack conversations.history API on an interval and triggers the workflow when new messages matching the configured filters are posted in a channel.

Credentials

Slack

Properties

Property	Key	Type	Required	Default	Possible values	Applies when
Poll Interval	pollIntervalMs	number	Yes	60000	Interval in milliseconds to check for new messages (minimum 60 seconds)	Always
Event	event	options	Yes	messagePosted	messagePosted (Message Posted)	Always
Channel ID	channelId	string	Yes	''	Slack channel ID to monitor, e.g. C1234567890	Always
Output	output	options	No	simple	simple (Simplified), raw (Raw)	Always
Filters	filters	object	No	{}	See sub-table	Always
Options	options	object	No	{}	See sub-table	Always

filters (object)

Property	Key	Type	Required	Default	Possible values
User ID	userId	string	No	''	Only trigger on messages from this Slack user ID
Text Contains	textContains	string	No	''	Only trigger on messages containing this text
Exclude Bot Messages	excludeBots	boolean	No	true	Exclude messages from bots
Message Subtype	subtype	string	No	''	Filter by message subtype, e.g. bot_message, file_share

options (object)

Property	Key	Type	Required	Default	Possible values
Max Messages Per Poll	maxMessages	number	No	10	Max messages processed per poll (clamped to 1-100)
Include Thread Replies	includeThreadReplies	boolean	No	false	Include messages that are thread replies

Notes

• channelId is required; the node throws if it's missing.
• If the channel has no messages in the poll window, or none survive filtering, the node returns null and the workflow does not trigger.
• Filters are applied after fetch: excludeBots drops messages with a bot_id or bot_message subtype, and thread replies (thread_ts set and different from ts) are dropped unless includeThreadReplies is set.
• Emits one item containing messages (array) and a summary (count, channel, users, previews — first 50 characters of each message, pollInterval, polledAt).