Slack

💬

Slack

Send messages and manage channels in Slack

The Slack node provides comprehensive integration with Slack workspaces. You can send and manage messages, create and administer channels, interact with users, upload files, and manage reactions. All actions use the Slack Web API through an OAuth connection.

Before You Use This Node

What you may need	Where to set it up	Why it matters
Slack workspace connection	Connections	Create the Slack connection once, then reuse it in every Slack step.
Common channel IDs, user IDs, or message templates	Global Variables	Store frequently used Slack values once and reuse them safely.

Actions

Action	Description
slack:sendMessage	Post a message to a channel
slack:updateMessage	Edit an existing message
slack:deleteMessage	Remove a message from a channel
slack:createChannel	Create a new public or private channel
slack:listChannels	List channels in the workspace
slack:archiveChannel	Archive a channel
slack:inviteToChannel	Invite a user to a channel
slack:setChannelTopic	Set the topic of a channel
slack:listUsers	List all users in the workspace
slack:getUserInfo	Get detailed info about a specific user
slack:sendDirectMessage	Send a direct message to a user
slack:sendThreadReply	Reply to a message in a thread
slack:listMessages	List recent messages in a channel
slack:getChannelHistory	Retrieve message history for a channel
slack:pinMessage	Pin a message to a channel
slack:unpinMessage	Unpin a message from a channel
slack:setChannelPurpose	Set the purpose description of a channel
slack:renameChannel	Rename a channel
slack:leaveChannel	Make the bot leave a channel
slack:uploadFile	Upload a file to a channel
slack:addReaction	Add an emoji reaction to a message

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slack:sendMessage

Posts a new message to a Slack channel. Supports plain text, Markdown (mrkdwn), and Block Kit layouts.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel name (e.g., #general) or channel ID
message	string	Yes	Message text. Supports Slack mrkdwn formatting
blocks	array	No	Block Kit block array for rich layouts
unfurlLinks	boolean	No	Whether to unfurl URLs. Defaults to true

slack:updateMessage

Edits an existing message. Requires the ts (timestamp) of the original message.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
ts	string	Yes	Timestamp of the message to update
message	string	Yes	New message text

slack:deleteMessage

Deletes a message from a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
ts	string	Yes	Timestamp of the message to delete

slack:createChannel

Creates a new channel in the workspace.

Parameters

Parameter	Type	Required	Description
name	string	Yes	Channel name (lowercase, no spaces, max 80 chars)
isPrivate	boolean	No	Set to true for a private channel. Defaults to false
description	string	No	Channel description

slack:listChannels

Lists channels in the workspace with optional filtering.

Parameters

Parameter	Type	Required	Description
types	string	No	Comma-separated: public_channel, private_channel. Defaults to public_channel
limit	integer	No	Max channels to return. Defaults to 100
excludeArchived	boolean	No	Exclude archived channels. Defaults to true

slack:archiveChannel

Archives a channel so it becomes read-only.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name to archive

slack:inviteToChannel

Invites a user to a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
userId	string	Yes	Slack user ID to invite

slack:setChannelTopic

Sets the topic line displayed at the top of a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
topic	string	Yes	New topic text (max 250 chars)

slack:listUsers

Returns a list of all users in the workspace.

Parameters

Parameter	Type	Required	Description
limit	integer	No	Max users to return. Defaults to 100
includeLocale	boolean	No	Include locale info in response

slack:getUserInfo

Retrieves detailed profile information for a single user.

Parameters

Parameter	Type	Required	Description
userId	string	Yes	Slack user ID

slack:sendDirectMessage

Sends a direct message (DM) to a user.

Parameters

Parameter	Type	Required	Description
userId	string	Yes	Slack user ID of the recipient
message	string	Yes	Message text

slack:sendThreadReply

Replies to an existing message, creating or continuing a thread.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
threadTs	string	Yes	Timestamp of the parent message
message	string	Yes	Reply text

slack:listMessages

Lists recent messages in a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
limit	integer	No	Max messages to return. Defaults to 20

slack:getChannelHistory

Retrieves message history for a channel within a time range.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
oldest	string	No	Start of time range (Unix timestamp)
latest	string	No	End of time range (Unix timestamp)
limit	integer	No	Max messages. Defaults to 100

slack:pinMessage

Pins a message to a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
ts	string	Yes	Timestamp of the message to pin

slack:unpinMessage

Removes a pin from a message.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
ts	string	Yes	Timestamp of the message to unpin

slack:setChannelPurpose

Sets the purpose description for a channel (shown in channel details).

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
purpose	string	Yes	Purpose text (max 250 chars)

slack:renameChannel

Renames a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or current name
name	string	Yes	New channel name

slack:leaveChannel

Makes the bot leave a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name

slack:uploadFile

Uploads a file to a channel.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
fileName	string	Yes	Name for the uploaded file
content	string	Yes	Base64-encoded file content
title	string	No	File title displayed in Slack
initialComment	string	No	Message posted alongside the file

slack:addReaction

Adds an emoji reaction to a message.

Parameters

Parameter	Type	Required	Description
channel	string	Yes	Channel ID or name
ts	string	Yes	Timestamp of the message
emoji	string	Yes	Emoji name without colons (e.g., thumbsup)

Rate Limits

Slack API enforces rate limits on all methods. Automation Hub handles rate limiting automatically with retry, but you should be aware of the limits when designing workflows:

• Tier 1 (posting messages, uploading files): approximately 1 request per second.
• Tier 2 (updating messages, setting topics): approximately 20 requests per minute.
• Tier 3 (reading channels, listing users): approximately 50 requests per minute.

When a rate limit is hit, Slack returns HTTP 429 with a Retry-After header. Automation Hub retries automatically after the specified delay.

For bulk operations (e.g., sending notifications to many channels), add delays between steps or batch your operations to stay within limits.

Message Formatting

Slack uses mrkdwn (not standard Markdown) for text formatting:

Format	Syntax	Example
Bold	*text*	bold text
Italic	_text_	italic text
Strikethrough	~text~	strikethrough
Inline code	`code`	code
Code block	```code```	Multi-line code
Link	<https://example.com|Click here>	Hyperlink with display text
User mention	<@U12345>	Mentions a specific user
Channel broadcast	<!channel>	Notifies everyone in the channel
Here broadcast	<!here>	Notifies active members only

For rich layouts with buttons, sections, and dividers, use the blocks parameter with Block Kit JSON. Always include a message as a plain text fallback even when using blocks, since some contexts (notifications, accessibility tools) only display the text fallback.

Common Problems

Symptom	Likely Cause	Fix
Message not posted	Bot is not a member of the channel, or wrong channel name/ID	Invite the bot to the channel. Use channel ID instead of name for reliability
Permission denied	OAuth token missing required scopes	Check that the bot token has the scopes listed in the Connection section below
Channel not found	Using channel name for a private channel	Use the channel ID instead of the channel name for private channels
File upload failed	File exceeds size limit	Slack file size limits vary by plan. Check your workspace plan limits
Thread reply not appearing	Incorrect threadTs value	Verify that threadTs matches the ts of the parent message exactly
Bot cannot see private channels	Bot has not been invited	Invite the bot to the private channel before attempting any action on it

Connection

Requires a Slack connection configured with an OAuth Bot Token. The token must have the following scopes depending on which actions you use:

• chat:write -- Send, update, and delete messages
• channels:read, groups:read -- List channels
• channels:manage, groups:write -- Create, archive, rename channels; set topic/purpose
• channels:history, groups:history -- Read message history
• users:read -- List users and get user info
• files:write -- Upload files
• reactions:write -- Add reactions
• pins:write -- Pin and unpin messages

Configure the connection in the Global Configurator under Connections > Slack.

Output

All Slack actions return a response with a status field and action-specific data:

For list operations, the data field contains an array of results along with pagination metadata when applicable.