Slack Trigger

Receive Slack messages and events as workflow triggers.

When to Use

Use Slack Trigger when:

You want to run a workflow when someone posts a message or mentions your bot
You need to react to emoji reactions or channel activity
Slack is the event source and your workflow runs asynchronously

For sending messages back to Slack, pair this with Slack Send Message.

Output

Handle	Type	Description
`payload`	object	Normalized Slack event payload

The payload (accessed as {{ slack.* }}) shape:

Field	Type	Description
`user`	string	Slack user ID of the event author
`channel`	string	Channel ID where the event occurred
`text`	string	Message text (for message and mention events)
`timestamp`	string	Slack message timestamp (`ts`)
`thread_ts`	string	Thread parent timestamp, if the message is in a thread
`event_type`	string	Event type (e.g. `message`, `app_mention`, `reaction_added`)
`raw_event`	object	Full Slack event object for advanced use cases

Settings

Events

Setting	Type	Default	Description
`event_types`	multi-select	`message`, `app_mention`	Slack event types to listen for: `message`, `app_mention`, `reaction_added`, `message.channels`

Filters

Setting	Type	Default	Description
`channel_filter`	string	—	Only trigger for events in this channel ID. Leave empty to accept all channels.

Testing

Setting	Type	Default	Description
`mockPayload`	code editor (JSON)	Sample Slack event JSON	JSON body to inject when running this workflow locally for testing.

Required Secrets

Configure these on the Env Vars page:

Env Var	Description
`SLACK_BOT_TOKEN`	Bot User OAuth Token (`xoxb-...`) from your Slack app
`SLACK_SIGNING_SECRET`	Signing secret used to verify incoming Slack requests

Example

Canvas

React to bot mentions and reply in the same thread:

Create a Slack App at api.slack.com/apps
Enable Event Subscriptions and set the Request URL to your deployed trigger endpoint on triggers.tensorify.io
Subscribe to bot events matching your event_types setting
Install the app and add SLACK_BOT_TOKEN and SLACK_SIGNING_SECRET as env vars
Set event_types to app_mention
Add a Slack Send Message node — set Channel to {{ slack.channel }}, Thread Timestamp to {{ slack.thread_ts }}, and Message Text to your response

Access event data in downstream nodes:

{{ slack.user }}
{{ slack.text }}
{{ slack.channel }}
{{ slack.event_type }}

The plugin handles Slack's URL verification challenge automatically.

TSL

import slack from @tensorify/slack-trigger:1.0.0
import slack_send from @tensorify/slack-send-message:1.0.0

node trigger @tensorify/slack-trigger:1.0.0 {
    event_types = ["app_mention"]
    channel_filter = ""
}

node reply @tensorify/slack-send-message:1.0.0 {
    channel = "{{ slack.channel }}"
    thread_ts = "{{ slack.timestamp }}"
    text = "Thanks for mentioning me, <@{{ slack.user }}>!"
}

trigger.payload -> reply.input

Common Gotchas

Bot messages ignored: Slack does not deliver bot-authored messages by default. Subscribe to app_mention if you want the bot to respond when tagged.
Missing scopes: Ensure your Slack app has the OAuth scopes required for the events you subscribe to (e.g. channels:history, app_mentions:read).
Channel filter: Use the channel ID (e.g. C01234ABCDE), not the channel name.
Signing secret required: Requests without a valid signature are rejected. Double-check SLACK_SIGNING_SECRET matches your app settings.