Automate Blog Content Creation with n8n: OpenAI Generation, Google Sheets Topics, Email Approval & Revisions

Input pending topics from Google Sheets → AI generates SEO blog posts → email human approval → revise based on feedback or archive

Who

Digital marketers scaling SEO content, bloggers maintaining publishing schedules, small business owners without writing resources

You get

Automatically fetches pending topics from Google Sheets on a schedule, generates 800–1200 word SEO articles using GPT-4 series models, sends them for email approval, and archives approved content back to Sheets with one-click revision support

You need

n8n · Google Sheets · Gmail

Steps

1. Set up the schedule trigger

   Add a Schedule Trigger node in n8n and configure the interval (e.g., hourly or daily). The workflow will automatically start at each scheduled time.

2. Fetch pending topic from Google Sheets

   Configure the Get Topic from Google Sheets node: connect your Google account, enter the document ID, and ensure a sheet named Topic List exists with Topic (column A) and Status (column B). The node filters for Status = Pending and returns the first matching topic title and row number.

3. AI generates SEO-optimized blog post

   The Copywriter AI Agent node receives the topic, calls the OpenAI Chat Model (default gpt-4o-mini, switchable to gpt-4o or gpt-4 in the node) together with Simple Memory and Structured Output Parser, and outputs JSON containing title and content. The prompt requires an 800–1200 word, SEO-friendly Markdown article with hierarchical headings.

   Execution prompt · Source text。Copywriter AI Agent node text parameter (System Prompt / Define Prompt)

   Copy prompt

   =You are an expert-level SEO content strategist and copywriter with years of experience writing high-performing blog posts.
   
   Your task is to:
   
   1. Improve the provided topic title by generating a better, SEO-optimized blog post title that is more attractive and ranks well on search engines.
   
   2. Write a complete blog post based on the improved title. The post must:
   - Be between 800–1200 words
   - Use a clear, conversational, and engaging tone
   - Be SEO-friendly with natural keyword integration
   - Start with a hooking introduction that introduces the topic smoothly
   - Use headings and subheadings (H1 for the title, H2 for main sections, H3 for supporting points)
   - Use bullet points or numbered lists where helpful
   - Have a strong conclusion that summarizes the key points and includes a call-to-action or final insight
   - Ensure smooth flow and concise, informative paragraphs
   
   3. Output the result as a JSON object with this format:
   
   ```json
   {
     "title": "Improved SEO-Optimized Title",
     "content": "Full blog post content in markdown format"
   }
   ```
   
   Here is the topic you should improve and write about:
   {{ $json.Topic }}
   
   Generate the improved title and the full blog post now.

4. Send email for human approval

   The Set Data node splits the AI output into Topic Title and Content fields, passing them to the Send Content for Approval (Gmail) node. This node uses the sendAndWait operation to send an email containing the title and body, plus an approval form with a dropdown (Yes / No / Cancel) and a Content Feedback text area. The workflow pauses until a response is received.

5. Branch based on approval result

   The Approval Result (Switch) node reads the Approve Content? field from the form response: Yes proceeds to archiving; No enters revision; Cancel also updates the topic status to Completed (no further generation).

6. Revise content based on feedback

   If the result is No, the Copywriter Revision Agent node sends the original topic, user feedback, and original draft to the same OpenAI Chat Model, producing a revised article. Requirements are to preserve strengths, apply all feedback, and maintain 800–1200 words with SEO structure. After revision, the content returns to Set Data and re-enters the approval loop.

   Execution prompt · Source text。Copywriter Revision Agent node text parameter (System Prompt / Define Prompt)

   Copy prompt

   =You are an expert-level copywriter with strong SEO knowledge and a clear, engaging writing style. Your task is to revise an existing blog post based on the given topic and user feedback.
   
   Here are your responsibilities:
   - Carefully apply all of the user's feedback to improve the blog post.
   - Preserve the good parts of the original content, but rewrite or adjust areas based on the feedback.
   - Keep the tone friendly, professional, and easy to read.
   - Organize the blog post with clear headings and subheadings.
   - Use bullet points or numbered lists when it makes the content clearer.
   - Ensure a strong hook in the introduction and a solid conclusion with a call-to-action or takeaway.
   - Aim for a length between 800–1200 words unless the feedback suggests otherwise.
   
   Here is the topic title:
   {{ $('Get Topic from Google Sheets').item.json.Topic }}
   
   Here is the user's feedback:
   {{ $('Send Content for Approval').item.json.data['Content Feedback'] }}
   
   Here is the original content:
   {{ $('Copywriter AI Agent').item.json.output }}
   
   Now, rewrite the blog post using this input, fully incorporating the feedback.

7. Update status and archive final draft

   After approval (Yes) or cancellation (Cancel), the Update Topic Status on Google Sheets node sets the topic's Status to Completed to prevent duplicate processing. Then the Add Generated Content to Google Sheets node appends the final title, content, and generation date to the Generated Content sheet, completing the archive.

You are assisting with reproducing n8n template #4371: automated blog content generation with email approval. First confirm the user has an n8n instance, an OpenAI API key, Google Sheets and Gmail OAuth2 credentials, and has copied the author's Google Sheet template. Then guide configuration in this order: 1) import workflow.json; 2) fill in document ID and email; 3) check credentials on each node; 4) test with one Pending topic. Do not perform sensitive actions (like sending real emails) on the user's behalf.