n8n Automated LinkedIn Posting: OpenAI Content Generation with Google Sheets Approval and Email Workflow

Read from Google Sheets → OpenAI generates LinkedIn post → Gmail approval → conditional posting with status writeback

Who

Marketing teams or social media operators needing a content approval workflow

You get

Automatically pull pending content from a spreadsheet, generate a LinkedIn post with AI, get email approval, then publish and update sheet status

You need

n8n · Google Sheets · Gmail · LinkedIn

Steps

1. Prepare the Google Sheet

   Create a new Google Sheet with columns: Post Description, Instructions, Image (URL, optional), Status, Output, Post Link, and row_number (for precise updates). Add a test row and set Status to Pending.

2. Configure n8n credentials

   In n8n, create and assign credentials to the respective nodes: a) Google Sheets OAuth2; b) Gmail OAuth2; c) OpenAI API Key; d) LinkedIn OAuth2. Update the credentials IDs in the workflow JSON for each node.

3. Set trigger and AI model

   In the Schedule Trigger node, set the interval (e.g., every morning at 9 AM). In the OpenAI Chat Model node, select a model (default gpt-4o-mini, or gpt-4o). Adjust the prompt in the Generate Post Content node if you want to change the writing style.

4. Generate content and send approval email

   The workflow reads the first row where Status is Pending, uses the Generate Post Content node to call OpenAI for the post body, formats it via Data Formatting 1, and sends it to the approver via Gmail with a custom form: dropdown Yes/No/Cancel and a textarea for change requests.

   Execution prompt · Source text。Generate Post Content node messages.messageValues[0].message (System instruction)

   Copy prompt

   =You are an expert social media and LinkedIn content writer.
   
   You will be provided with:
   - A brief post description
   - Specific instructions from the user
   
   Please follow these steps:
   
   1. Initial Creation:
   If you are given a post description and instructions, write a polished, professionally worded LinkedIn post suitable for sharing. Strictly follow the instructions and ensure the message is engaging and succinct.
   If instructed, add a call to action or particular phrase (for example, "Connect with me" at the bottom).
   
   2. Formatting:
   Keep the tone positive, inclusive, and professional.
   Add relevant hashtags in small case.
   Limit the content to within 1300 characters.
   Place the call to action or special instruction at the end if requested.
   Output ONLY the final LinkedIn post content. Do NOT include any explanations, markdown, headings, or commentary—just the post text, ready to copy and share on LinkedIn.

   Execution prompt · Source text。Generate Post Content node text field (User prompt)

   Copy prompt

   =# LinkedIn Post Generation
   
   ## Post Description:
   {{ $json["Post Description"] }}
   
   ## Instructions:
   {{ $json["Instructions"] }}
   
   ---
   
   **Task:**
   Using the information above, generate the content for a LinkedIn post:
   - Use the Description and Instructions to create a new post.
   - Ensure your output is positive, professional, clear, and follows all provided instructions and feedback.
   - Do not include any explanations, just the final post content only, ready to publish on LinkedIn.
   - Limit to 1300 characters.
   - If the user demands to keep the same post as the Post Descrioption (in the instructions), then keep the same post content as provided in the Post Description, and output it.

5. Handle approval and publish

   The Content Confirmation Logic (Switch node) routes by response: Yes → check for image URL; if present download and post with image (Post With Image), else text-only post (Post Without Image), then update Google Sheet to Completed with post link. No → pass change requests to Regenerate Post Content and resend for approval. Cancel → update Google Sheet to Cancelled.

   Execution prompt · Source text。Regenerate Post Content node text field

   Copy prompt

   =Apply the modification requests on the following LinkedIn post. Besides applying the reqested modifications, return the same linkedin post.
   
   LinkedIn post:
   ```
   {{ $('Data Formatting 1').item.json['Post Content'] }}
   ```
   
   Change requests:
   {{ $('Send Content Confirmation').item.json.data['Any Changes?'] }}
   
   **Task:**
   Using the information above, update the LinkedIn post content:
   - Do not include any explanations, just the final post content only (with all the change requests included in the post), ready to publish on LinkedIn.
   - Limit to 1300 characters.
   - If the user demands to keep the same post as the Post Description (in the instructions), then keep the same post content as provided in the Post Description, and output it.

   Execution prompt · Source text。Post With Image node text field

   Copy prompt

   ={{ $('Data Formatting 1').item.json['Post Content'] }}

You are setting up an n8n workflow that auto-generates LinkedIn content from Google Sheets and publishes after email approval. Before starting, confirm: 1) The Google Sheet is created with required columns; 2) All four credentials (Google Sheets, Gmail, OpenAI, LinkedIn) are configured in n8n; 3) You have imported the workflow JSON or built the nodes manually. To change the writing style, edit the system message and user prompt in the Generate Post Content node.