Slack Post

The Slack Post node sends messages to Slack channels. Use it for notifications, alerts, summaries, and any communication that should reach your team in Slack.

Overview

Prerequisites

• Slack integration connected (Setup Guide)
• Agents bot invited to target channel(s)

Configuration

Channel Parameter

Specify the channel using:

Channel ID (recommended):

"C0123456789"

Channel name:

"#sales-updates"

Dynamic from data:

json.slackChannel

How to find Channel ID:

1. Right-click channel name in Slack
2. Select "View channel details"
3. Scroll to bottom, copy the Channel ID

Text Parameter

Message content using Liquid templates:

📋 *Meeting Summary*

*{{ json.meeting.title }}*

{{ json.summary }}

_Posted by Agents_

Input Schema

Accepts any data from upstream. Access it via json in templates.

Output Schema

Success Output

{
  "success": true,
  "messageId": "1234567890.123456",
  "channel": "C0123456789",
  "timestamp": "2024-01-15T14:30:00Z"
}

Error Output

{
  "error": "channel_not_found",
  "message": "Channel C0123456789 not found or bot not invited",
  "channel": "C0123456789"
}

Examples

Basic Example: Simple Notification

Send a simple notification when a meeting ends.

Configuration:

Channel: "#sales-updates"

Text:

Meeting "{{ json.meeting.title }}" has ended.

Example: Formatted Summary

Send a well-formatted meeting summary.

Configuration:

Channel: "C0123456789" (using channel ID)

Text:

📋 *Meeting Recap: {{ json.meeting.title }}*

*Date:* {{ json.meeting.startTime | date: "%B %d, %Y at %I:%M %p" }}

*Attendees:*
{% for attendee in json.meeting.attendees %}
• {{ attendee.name }}
{% endfor %}

*Summary:*
{{ json.summary }}

{% if json.actionItems.size > 0 %}
*Action Items:*
{% for item in json.actionItems %}
• {{ item }}
{% endfor %}
{% endif %}

Example: Conditional Formatting

Different formatting based on sentiment.

Text:

{% if json.sentiment == "positive" %}
✅ *Positive Meeting: {{ json.meeting.title }}*
{% elsif json.sentiment == "negative" %}
⚠️ *Needs Attention: {{ json.meeting.title }}*
{% else %}
📋 *Meeting Update: {{ json.meeting.title }}*
{% endif %}

{{ json.summary }}

Example: Mention Users

Include Slack mentions in messages.

Text:

Hey <@U0123456789>, the meeting with {{ json.contact.name }} just ended.

Key takeaway: {{ json.keyTakeaway }}

Note: Use Slack user IDs for mentions, not names. Format: <@USERID>

Example: Link to Meeting

Include clickable links.

Text:

*{{ json.meeting.title }}*

{{ json.summary }}

<{{ json.meetingUrl }}|View Meeting Details>

Slack Formatting Reference

Slack uses a specific formatting syntax:

Emojis

Use standard emoji shortcodes:

• :white_check_mark: → ✅
• :warning: → ⚠️
• :memo: → 📝
• :calendar: → 📅

Best Practices

1. Use Channel IDs

Channel IDs are more reliable than names:

• Names can change
• IDs are permanent
• Avoids confusion with similar names

2. Keep Messages Scannable

📋 *{{ json.meeting.title }}*

*TL;DR:* {{ json.oneSentenceSummary }}

<{{ json.detailsUrl }}|See full details>

3. Include Context

Always include enough context for readers:

• What meeting/deal this relates to
• When it happened
• Why they're receiving this

4. Use Appropriate Channels

• High-volume alerts → dedicated alert channel
• Deal updates → deal-specific or team channel
• Urgent items → consider DM or SMS instead

5. Don't Over-Notify

• Batch related updates when possible
• Use conditional logic to filter noise
• Respect team's attention

Common Issues

"Channel not found" error

Causes:

• Invalid channel ID
• Bot not invited to private channel
• Channel was deleted

Solutions:

1. Verify channel ID is correct
2. Invite bot: /invite @Meetingflow Bot
3. Check channel still exists

Bot can post to some channels but not others

Cause: Bot not invited to private channels

Solution:

/invite @Meetingflow Bot

Message not appearing

Causes:

• Workflow succeeded but wrong channel
• Message in thread (not main channel)
• Slack API delay

Solutions:

1. Check output for actual channel posted to
2. Verify channel configuration
3. Wait a moment and refresh Slack

Formatting looks wrong

Cause: Mixing markdown and Slack syntax

Solution: Use Slack's formatting syntax (*bold* not **bold**)

Related Nodes

• If - Conditionally send messages
• AI Prompt - Generate message content
• Email Send - Alternative communication

Technical Details

Rate Limits

Slack has API rate limits:

• ~1 message per second per channel
• Higher limits for paid workspaces

The retry mechanism handles temporary rate limits automatically.

Message Size Limits

• Maximum message length: ~40,000 characters
• Recommended: Keep under 4,000 characters for readability

Bot Permissions

The Slack bot requires these scopes:

• chat:write - Post messages
• chat:write.public - Post to public channels without joining

For private channels, the bot must be explicitly invited.