Slack Adapter

A Transform Custom node that posts the message reaching it into a Slack channel.

Part of the Linkiir Adapters package — see requesting the package.

What it does

When a message arrives, the node posts its content to the configured channel as your Slack app. It can prefix the post with a mention, resolved from an email address, so the right person is notified.

upstream node  →  Slack Adapter  →  Slack channel

Common uses: alerting a support channel when a feed errors, and announcing that a batch finished.

Before you start

In your Slack workspace:

Create a Slack app, or use an existing one.
Under OAuth & Permissions, add the scopes the app needs to post messages, and to look up users by email if you plan to use mentions.
Install the app to the workspace and copy the Bot User OAuth Token.
Invite the app to the target channel. A bot that is not in the channel cannot post to it.
Copy the channel ID from the channel's URL.

Treat the bot token as a credential

Enter the token in the API Token field, which is masked and encrypted in the project. Anyone holding it can post as your app. Rotate it in Slack if it is ever exposed.

Set it up

Open the Slack node in the Workflow Builder and click Edit.
Fill in the fields:

Field Value
API Token The Bot User OAuth Token
Channel ID The target channel's ID
Mention Email Optional. The email of a workspace member to mention
Set Live Mode off, then Save.
Send one message through and check the log — it shows the post that would have been made.
Turn Live Mode on and send another. The message appears in the channel.

Field	Value
API Token	The Bot User OAuth Token
Channel ID	The target channel's ID
Mention Email	Optional. The email of a workspace member to mention

Configuration reference

Field	Type	Default	Purpose
API Token	password	(empty)	Slack Bot User OAuth Token
Channel ID	string	(empty)	Target channel identifier
Mention Email	string	(empty)	Email resolved to a user mention on the post. Leave empty for no mention
Live Mode	bool	`true`	When off, nothing is sent to Slack
Verify TLS	bool	`true`	Verify Slack's TLS certificate

Verify it worked

With Live Mode on, the message appears in the channel within a second or two.
With Mention Email set, the post begins with that person's mention.
The node log records the outcome for each attempt.

If it didn't work

Symptom in the log	Cause	Fix
`SLACK_ERROR: invalid_auth`	The token is wrong or has been revoked	Regenerate the Bot Token in the Slack app settings and re-enter it
`SLACK_ERROR: channel_not_found`	The channel ID is wrong	Copy the ID again from the channel's URL
`SLACK_ERROR: not_in_channel`	The app was never invited to that channel	Invite it, then retry
`SLACK_ERROR: missing_scope`	The app lacks a scope the call needs	Add the scope under OAuth & Permissions and reinstall the app
`USER_NOT_FOUND`	Mention Email is not a member of the workspace	Use a member's email, or clear the field
`REQUEST_FAILED` or a timeout	The server cannot reach Slack	Check outbound network access and DNS
Posts arrive empty	The upstream node is sending nothing	Check the source or transform produces content
Nothing is posted, no error	Live Mode is off	Turn Live Mode on

What it does​

Before you start​

Set it up​

Configuration reference​

Verify it worked​

If it didn't work​

Next​