Automate Gmail Newsletters to LinkedIn Posts with n8n & OpenAI

1. Opening Problem Statement

Meet Sarah, a busy AI content curator at a tech startup. Every morning, she receives numerous newsletters from her favorite AI news sources like Decode AI. While these newsletters are packed with valuable information about new AI tools, product launches, and investments, Sarah spends hours manually reading, summarizing, and converting these into engaging LinkedIn posts for her network. With mounting newsletter volume, this tedious task drains her time and creativity, delaying her ability to share timely updates and missing growth opportunities on LinkedIn.

The problem? Sarah wastes up to 3 hours daily parsing long emails and drafting posts that often lack consistent style or tone. She wants to automate this process to stay ahead and share sharp, witty social content promptly without the repetitive manual work.

2. What This Automation Does

This n8n workflow specifically transforms Gmail newsletters from a predefined sender into polished LinkedIn posts using OpenAI’s powerful language model. Here’s what it accomplishes once set up and triggered:

• Automatically fetch latest newsletters from Gmail filtering emails sent by a specific sender (e.g., [email protected]).
• Extract and summarize the top 5 factual news items—like new AI tools or investments—using an OpenAI node tailored to omit promotional content.
• Split each news item individually for focused processing.
• Generate unique, witty LinkedIn posts from each item applying a style prompt emphasizing clarity and subtle humor.
• Post directly to LinkedIn via the LinkedIn node authenticated with OAuth2.
• Save hours weekly by eliminating manual review, summarization, and posting tasks.

3. Prerequisites ⚙️

• Gmail Account 📧 configured to receive newsletters and allow API access via OAuth2.
• OpenAI Account 🔑 with API credentials to use the provided language model for summarization and content generation.
• LinkedIn Developer Account 🔑 with OAuth2 credentials to post on behalf of your profile or company page.
• n8n Automation Platform ⏱️ account with the ability to connect all above services and run workflows. You may self-host for improved control and privacy, for example using providers like Hostinger.

4. Step-by-Step Guide

Step 1: Manual Trigger Setup

Start with the Manual Trigger node named “When clicking ‘Test workflow’”. This node allows you to run the workflow on demand during testing or scheduling.
To configure:

• Open n8n editor, click Add Node → Manual Trigger.
• Rename it to “When clicking ‘Test workflow’” for clarity.
• This node doesn’t require parameters but acts as the starting point.
• After setting, you’ll see a ‘Execute Workflow’ button available in n8n UI to trigger the flow anytime.

Common Mistake: Forgetting manual trigger limits your ability to test the workflow interactively before automating.

Step 2: Fetch Newsletters with Gmail Node

Next place the Gmail node configured to pull emails from a specific sender:

• Click Add Node → Gmail.
• Rename it “Gmail” or “Filter Gmail Newsletter”.
• On the node settings, set Operation to getAll and add a filter to only include emails from sender [email protected].
• Ensure OAuth2 credentials are linked with your Gmail account for API access.
• Set the limit to 1 or any number of emails you want to process per run.
• Test the node to fetch recent newsletters matching criteria.

Outcome: The node downloads specified newsletters including all message content as JSON for downstream processing.

Common Mistake: Forgetting to correctly set the sender filter causes fetching unwanted emails, leading to irrelevant processing.

Step 3: Extract News Items Using OpenAI

Place the OpenAI node named “Extract News Items,” utilizing the Langchain integration for summarization:

• Add Node → OpenAI.
• Rename to “Extract News Items”.
• Use the model o3-mini-2025-01-31 for fast, accurate summarization.
• Enter this prompt message in the node under messages:

  =Given the following newsletter content, identify and summarize the 5 main news items. Focus on factual updates like new AI tools, product launches, or strategic investments. For each item, extract a headline and provide a concise summary. Please ignore purely promotional sections (e.g., calls to book demos or product advertisements).
  
  
  {{ $json.text }}
  

• Link your OpenAI API credentials.
• The output is a structured JSON with news item headlines and summaries for further nodes.

Common Mistake: Not using the specific prompt as given might produce promotional or irrelevant outputs.

Step 4: Split News Items Individually

Use the Split Out node to handle each news item separately:

• Add Node → Split Out.
• Configure the node to split the array located at message.content.news_items.
• This allows each news item to process independently for post generation.

Outcome: If 5 news items exist, you get 5 items output from this node sent downstream.

Common Mistake: Incorrectly specifying the field to split results in errors or empty outputs.

Step 5: Create LinkedIn Posts with OpenAI

Add a second OpenAI node named “Create LinkedIn Posts” for crafting posts:

• Choose model o3-mini-2025-01-31 again for consistent style.
• Use this prompt in messages:

  =Using the news item details below:
  
  Headline: {{ $json.headline }}
  Summary: {{ $json.summary }}
  
  Craft a concise, non-promotional LinkedIn post in a smart, deadpan style with subtle humor. Focus on clearly conveying the main points and insights so readers gain practical value. 
  - Break up the text into short paragraphs or bullet points for clarity.
  - Use line breaks where helpful.
  - End with an observation or question that encourages reflection—without being overly salesy or flashy.
  - Keep it under 80 words total.
  

• Again, connect the OpenAI API credentials.

Outcome: The OpenAI node generates ready-to-publish LinkedIn post content for each news item.

Common Mistake: Writing too long posts or ignoring the style prompt leads to less engaging content.

Step 6: Publish Posts on LinkedIn

Finally, link the LinkedIn node to post the generated content:

• Add Node → LinkedIn.
• Configure parameters to use the text from previous OpenAI node under message.content.
• Add LinkedIn account OAuth2 credentials.
• Set the person identifier for the post author (profile or company page ID).
• Test with sample data to confirm live posting.

Outcome: Each news summary becomes a new, intelligent LinkedIn post visible to your network.

Common Mistake: Not having correct OAuth2 scopes or person ID causes failures to post.

Step 7: Save a Workflow Overview for Clarity

Use the Sticky Note node to document the workflow internally:

• Add a Sticky Note at the start with all key details: workflow name, purpose, setup, and customization tips.
• This serves as a helpful reference for anyone revisiting or modifying the workflow later.

5. Customizations ✏️

• Tone Adjustment: In the “Create LinkedIn Posts” OpenAI node, tweak the prompt to change the post tone from deadpan humor to professional or enthusiastic by editing the message content.
• Sender Filter: In the Gmail node, update the email sender filter to process newsletters from other sources relevant to your industry.
• Post Scheduling: Add a Cron Trigger node before the Gmail node to automate daily or weekly checks instead of manual triggering.
• Additional Formatting: Insert a Function node between “Split Out” and “Create LinkedIn Posts” to add hashtags or mentions dynamically to each post.

6. Troubleshooting 🔧

Problem: “No emails fetched” from Gmail node

Cause: Incorrect sender filter or OAuth2 authentication failures.

Solution: Double-check the sender filter matches exactly the newsletter email, verify OAuth2 credentials, and run the Gmail test again.

Problem: “OpenAI node returns irrelevant summaries or promotional text”

Cause: Prompt not entered exactly or input JSON path incorrect.

Solution: Copy-paste the provided prompt verbatim, confirm the input message correctly references {{ $json.text }}, and test outputs before connecting further nodes.

Problem: “LinkedIn post fails to publish”

Cause: OAuth2 credentials missing necessary permissions or wrong person ID.

Solution: Review LinkedIn API app permissions, reauthenticate OAuth2 credentials, and ensure the person field corresponds to your LinkedIn user or company page ID.

7. Pre-Production Checklist ✅

• Verify Gmail node correctly fetches test newsletters from the target sender.
• Confirm OpenAI summaries accurately extract five main news items based on the sample input.
• Ensure Split Out node splits the news items array properly with no errors.
• Test OpenAI post generation for clear, concise, and stylistically consistent LinkedIn messages.
• Complete LinkedIn node authorization and do a dry run post to a test account or draft.
• Backup your workflow export in n8n before major changes or production rollout.

8. Deployment Guide

Once testing is complete and you’re satisfied with outputs, activate the workflow in n8n.

• Replace the Manual Trigger node with a Cron Trigger for automated scheduling if desired.
• Monitor logs for any failed executions within n8n’s execution panel.
• Update your prompt or node configurations as newsletter style or LinkedIn posting needs evolve.
• Consider setting up alert notifications in n8n if posts fail or content extracts incomplete.

9. FAQs

Can I use a different email provider instead of Gmail?

This workflow is built around the Gmail node’s OAuth2 integration for robust filtering and message extraction. You could adapt it by using IMAP or other email nodes but extra customization might be needed.

Does posting consume significant API quota on OpenAI?

Since this workflow uses concise prompts and a minimal weekly run (one to few emails), the credits consumed are moderate. Monitor OpenAI account usage to stay within your plan limits.

Is my LinkedIn account secure with OAuth2?

Yes, LinkedIn OAuth2 ensures tokens are securely handled by n8n without exposing your password. Always review app permissions.

How many newsletters can this workflow handle at once?

Currently set to process one email per run but can be adjusted. Bulk processing might slow down API responses and LinkedIn posting.

10. Conclusion

By following this blog tutorial, you have transformed a tedious manual process into an efficient automated pipeline that fetches, summarizes, crafts, and shares AI newsletter highlights on LinkedIn. This saves you several hours weekly, ensures timely and consistent social content, and boosts your professional visibility.

Next, consider automating other newsletter types or expanding to post on Twitter or other channels using similar OpenAI-powered nodes. This workflow is a strong foundation for intelligent social media automation tailored to your niche. Happy automating!