LinkedIn Post Automation with AI (GPT-4o) Generation & Slack Approval

Created by

Amit Mehta

Last update

Last update 5 months ago

How it Works

This workflow automates the creation and publishing of LinkedIn posts with AI-generated content and human approval via Slack, using Google Sheets, OpenAI (GPT-4), Slack Interactive Messages, and the LinkedIn API.

Whether you're a social media manager, content creator, or marketing professional, this workflow helps you maintain consistent LinkedIn presence and scale content creation while keeping human oversight — all managed from a simple spreadsheet.

🎯 Use Case

Ideal for:

Content Marketers managing multiple LinkedIn accounts
Personal Brand Builders maintaining regular posting schedule
Agencies handling client social media presence
Teams requiring content approval workflows

Setup Instructions

1. Prepare the Spreadsheet

File name: Linkedin Post
Main sheet structure:
| ID | Linkedin Post Title | Status | Image URL |
Groups sheet structure:
| GroupIds |
Add post topics and set their Status as Pending

2. Configure Google Sheets Nodes

Connect your Google account to:

Linkedin-Post-Topic (Trigger node)
Update-Status
Get-Group-id

3. Add API Credentials

OpenAI API Key → for GPT-4 content generation
Slack OAuth Token → for approval messages
LinkedIn Access Token → for posting content
HTTP Header Auth → Bearer token for LinkedIn API

4. Configure Webhooks

Set up Slack Interactive Components webhook
Point Request URL to your N8N webhook endpoint
Enable interactive messages in Slack app

5. Activate the Workflow

Once live, the workflow will:

Monitor spreadsheet for new topics every minute
Generate LinkedIn post using GPT-4
Send to Slack for approval/editing
Upload image to LinkedIn
Publish to profile and groups
Update spreadsheet status to Posted

🔁 Workflow Logic

Trigger: New/updated row with Pending status
Generate: AI creates engaging LinkedIn post
Approve: Slack message for review/edit
Process: Handle approval response
Upload: Register and upload image
Publish: Post to LinkedIn profile & groups
Update: Mark as Posted in sheet

🧩 Node Descriptions

Node Name	Description
Linkedin-Post-Topic	Monitors spreadsheet for new post topics
Validate-Status	Filters only 'Pending' items
Limit	Processes one item at a time
Linedin-Post-Creator	Generates post content using GPT-4
Format-Content	Prepares content for Slack display
Approval-on-Slack	Sends interactive approval message
Webhook	Receives Slack button responses
Format-Response	Extracts edited content from Slack
Set-Final-Message	Prepares approved content
Linkedin-User-Detail	Fetches LinkedIn user info
Register Image	Initiates LinkedIn image upload
Upload Image	Uploads image to LinkedIn
Linkedin-post	Publishes to personal profile
Get-Group-id	Retrieves LinkedIn group IDs
Post-Linkedin-Groups	Posts to multiple groups
Update-Status	Marks as completed in sheet

🛠️ Customization Tips

Adjust AI prompt for brand voice and hashtags
Change Slack approver or add multiple reviewers
Modify posting schedule with delay nodes
Add analytics tracking with additional API calls
Filter groups based on specific criteria
Include URL shortening for tracking

📒 Suggested Sticky Notes for Workflow

Node/Section	Sticky Note Content
Linkedin-Post-Topic	"Triggers every minute for new posts in your spreadsheet"
Validate-Status	"Filters to process only 'Pending' items - prevents duplicates"
Linedin-Post-Creator	"Uses GPT-4 to generate LinkedIn content - customize prompt for your brand voice"
Approval-on-Slack	"Sends for human review - edit the Slack user to change approver"
Webhook	"Receives approval responses - ensure URL is configured in Slack app"
Register Image	"Initiates LinkedIn media upload - requires valid image URL from sheet"
Linkedin-post	"Publishes to your profile - update with your LinkedIn credentials"
Post-Linkedin-Groups	"Posts to multiple groups - add group IDs in Groups sheet"
Update-Status	"Marks as 'Posted' to prevent reprocessing"

💡 AI Prompt Configuration

The workflow uses a sophisticated prompt that:

Creates compelling hooks
Includes 3-4 informative paragraphs
Adds engagement questions
Inserts relevant emojis
Generates 4-6 hashtags
Formats with proper spacing

🔒 Security & Permissions

LinkedIn App Requirements:

r_liteprofile - Read profile data
r_emailaddress - Access email
w_member_social - Post content
rw_organization_admin - Group posting

Slack Bot Permissions:

chat:write - Send messages
im:write - Direct messages
users:read - User information

📎 Required Components

Component	Purpose
Google Sheet	Store post topics and status
LinkedIn App	API access for posting
Slack App	Interactive approval flow
OpenAI Account	GPT-4 content generation
N8N Instance	Workflow execution

🧪 Testing Tips

Start with one test topic marked as Pending
Verify Slack message appears correctly
Test both "Approve" and "Edit" buttons
Check image upload completes
Confirm post appears on LinkedIn
Verify status updates to Posted

⚠️ Common Issues & Solutions

LinkedIn API Errors:

Token expiration → Refresh access token
Rate limits → Add delays between posts
Group restrictions → Check posting permissions

Slack Integration:

Missing responses → Verify webhook URL
Button not working → Check interactive components
User not found → Confirm Slack user ID

Image Upload Failures:

Invalid URL → Validate image accessibility
Size limits → Compress images under 10MB
Format issues → Use JPEG or PNG only

📊 Workflow Benefits

Time Savings: 80% reduction in content publishing time
Consistency: Regular posting schedule maintained
Quality Control: Human review ensures brand standards
Scalability: Handle multiple accounts and groups
Flexibility: Easy to modify and extend

📎 Required Files

File Name	Purpose
Linkedin Post	Google Sheet to hold post topics and status