message/send

When to Use

• Incident alerts: DevOps monitoring detects a P1 failure and your workflow sends a formatted alert with severity, service name, and runbook link directly to #incidents.
• Order confirmations: An e-commerce workflow sends an order summary to a customer's DM immediately after checkout, including order number, items, and estimated delivery.
• Approval notifications: An approval workflow notifies the original requestor via DM when their request is approved or rejected, including the approver name and decision reason.
• Daily digest posts: A scheduled workflow aggregates nightly metrics (sales, active users, open tickets) and posts a formatted summary to #analytics every morning at 8 AM.
• Cross-team coordination: An HR onboarding workflow sends a welcome message to #engineering, #design, and #general when a new hire joins, with their role, start date, and Slack handle.

Configuration

Connection

Operation

Sample Configuration

{
  "resource": "message",
  "operation": "send",
  "botToken": "{{ $credentials.slackBotToken }}",
  "channel": "C04X9ABCDEF",
  "text": "*Alert:* Service `payments-api` is down in `us-east-1`. Severity: *P1*. <https://runbooks.internal/payments-api-down|View Runbook>",
  "username": "AlertBot",
  "iconEmoji": ":rotating_light:",
  "blocksJson": "[{\"type\":\"section\",\"text\":{\"type\":\"mrkdwn\",\"text\":\"*:rotating_light: P1 Incident*\\nService: `payments-api`\\nRegion: `us-east-1`\\nDetected: {{ $now }}\"}},{\"type\":\"actions\",\"elements\":[{\"type\":\"button\",\"text\":{\"type\":\"plain_text\",\"text\":\"View Runbook\"},\"url\":\"https://runbooks.internal/payments-api-down\",\"style\":\"danger\"}]}]"
}

Validation Errors

Output

Success Port

Fires after the message is confirmed delivered by Slack. The messageTs value is the unique timestamp/ID of the new message and is needed for update, delete, reply, and permalink operations.

Error Port

Fires when Slack rejects the request (invalid channel, permission error, malformed blocks, etc.) or when the network call fails. Always connect the error port to a logging or alerting node in production workflows.

Sample Output

{
  "messageTs": "1716700412.087200",
  "channel": "C04X9ABCDEF",
  "userId": "U0LAN0Z89",
  "text": "*Alert:* Service `payments-api` is down in `us-east-1`.",
  "status": "ok",
  "errorCode": "",
  "payload": {
    "ok": true,
    "channel": "C04X9ABCDEF",
    "ts": "1716700412.087200",
    "message": {
      "type": "message",
      "subtype": "bot_message",
      "text": "*Alert:* Service `payments-api` is down in `us-east-1`.",
      "ts": "1716700412.087200",
      "bot_id": "B0LAN0Z89"
    }
  }
}

Expression Reference

Node Policies & GuardRails

Examples

Incident Alert with Block Kit

{
  "resource": "message",
  "operation": "send",
  "botToken": "{{ $credentials.slackBotToken }}",
  "channel": "C04INCIDENTS",
  "text": "P1 Incident: payments-api is down in us-east-1",
  "iconEmoji": ":rotating_light:",
  "blocksJson": "[{\"type\":\"header\",\"text\":{\"type\":\"plain_text\",\"text\":\":rotating_light: P1 Incident\"}},{\"type\":\"section\",\"fields\":[{\"type\":\"mrkdwn\",\"text\":\"*Service:*\\n`{{ $input.serviceName }}`\"},{\"type\":\"mrkdwn\",\"text\":\"*Region:*\\n`{{ $input.region }}`\"},{\"type\":\"mrkdwn\",\"text\":\"*Severity:*\\n{{ $input.severity }}\"},{\"type\":\"mrkdwn\",\"text\":\"*Detected:*\\n{{ $now }}\"}]},{\"type\":\"actions\",\"elements\":[{\"type\":\"button\",\"text\":{\"type\":\"plain_text\",\"text\":\"View Runbook\"},\"url\":\"{{ $input.runbookUrl }}\",\"style\":\"danger\"}]}]"
}

Posts a structured incident card to #incidents with service details and a runbook button. The messageTs from the success port is stored and used by a later message/update node to change the card status to "Resolved" when the incident closes.

DM Order Confirmation

{
  "resource": "message",
  "operation": "send",
  "botToken": "{{ $credentials.slackBotToken }}",
  "channel": "{{ $input.customerSlackUserId }}",
  "text": "Your order #{{ $input.orderId }} has been confirmed. Estimated delivery: {{ $input.deliveryDate }}."
}

Sends a plain-text DM directly to a customer's Slack user ID. The user ID is resolved earlier in the workflow from the customer's profile in the CRM via the user/get node using their email address.

Threaded Follow-up Reply

{
  "resource": "message",
  "operation": "send",
  "botToken": "{{ $credentials.slackBotToken }}",
  "channel": "{{ $output.postDigest.channel }}",
  "text": "_Update at {{ $now }}:_ All 42 overnight jobs completed. Total records processed: *{{ $input.recordCount }}*.",
  "threadTs": "{{ $output.postDigest.messageTs }}"
}

Replies in the thread of a previously sent digest message. $output.postDigest.messageTs references the timestamp returned by an earlier message/send node named postDigest. This keeps all status updates inside a single thread rather than flooding the channel.