Slack Trigger

Type ID: slackTrigger  ·  Kind: Trigger  ·  Trigger style: poll  ·  Trace: CHAIN

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	Shown 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

Fires via poll(). Requires channelId (poll and execute both throw if missing). Uses a stateless time window: each poll calls conversations.history with oldest = (now - pollIntervalMs) and latest = now as Unix timestamps, inclusive: true, and limit = maxMessages.

Filtering is applied client-side after fetch: messages are dropped if they don't match userId, if textContains is set and the text doesn't include it, if excludeBots is set and the message has a bot_id or bot_message subtype, if subtype is set and doesn't match, or (unless includeThreadReplies) if the message is a thread reply (thread_ts set and not equal to ts). simple output maps each message to a flattened object (ts, type, user, text, channel, threadTs, isBot, subtype, attachments, files, reactions, edited); raw returns the message as received.

When the channel returns no messages in the window, or none survive filtering, the node returns null and the workflow does not trigger. Otherwise it emits one item whose json contains messages (array) and a summary with count, channel, users, previews (first 50 chars per message), pollInterval, and polledAt.

The trigger() method delegates to poll(). When used as a non-root internal node, execute() returns a wait item on the poll channel.