End-to-end Ai blog research and writer with Gemini AI, Supabase and Nano-Banana

Blog Research and Writer n8n Workflow - Ai Blog Writer

Fully automated blog creation system using n8n + AI Agents + Image Generation

Example Blog

Overview

This workflow automates the entire blog creation pipeline—from topic research to final publication. Three specialized AI agents collaborate to produce publication-ready blog posts with custom images, all saved directly to your Supabase database.

How It Works

1. Research Agent (Topic Discovery)

• Triggers: Runs on schedule (default: daily at 4 AM)
• Process:
  • Fetches existing blog titles from Supabase to avoid duplicates
  • Uses Google Search + RSS feeds to identify trending topics in your niche
  • Scrapes competitor content to find content gaps
  • Generates detailed topic briefs with SEO keywords, search intent, and differentiation angles
• Output: Comprehensive research document with SERP analysis and content strategy

2. Writer Agent (Content Creation)

• Triggers: Receives research from Agent 1
• Process:
  • Writes full blog article based on research brief
  • Follows strict SEO and readability guidelines (no AI fluff, natural tone, actionable content)
  • Structures content with proper HTML markup
  • Includes key sections: hook, takeaways, frameworks, FAQs, CTAs
  • Places image placeholders with mock URLs (https://db.com/image_1, etc.)
• Output: Complete JSON object with title, slug, excerpt, tags, category, and full HTML content

3. Image Prompt Writer (Visual Generation)

• Triggers: Receives blog content from Agent 2
• Process:
  • Analyzes blog content to determine number and type of images needed
  • Generates detailed 150-word prompts for each image (feature image + content images)
  • Creates prompts optimized for Nano-Banana image model
  • Names each image descriptively for SEO
• Output: Structured prompts for 3-6 images per blog post

4. Image Generation Pipeline

• Process:
  • Loops through each image prompt
  • Generates images via Nano-Banana API (Wavespeed.ai)
  • Downloads and converts images to PNG
  • Uploads to Supabase storage bucket
  • Generates permanent signed URLs
  • Replaces mock URLs in HTML with real image URLs
• Output: Blog HTML with all images embedded

5. Publication

• Final blog post saved to Supabase blogs table as draft
• Ready for immediate publishing or review

Key Features

✅ Duplicate Prevention: Checks existing blogs before researching new topics
✅ SEO Optimized: Natural language, proper heading structure, keyword integration
✅ Human-Like Writing: No robotic phrases, varied sentence structure, actionable advice
✅ Custom Images: Generated specifically for each blog's content
✅ Fully Structured: JSON output with all metadata (tags, category, excerpt, etc.)
✅ Error Handling: Automatic retries with wait periods between agent calls
✅ Tool Integration: Google Search, URL scraping, RSS feeds for research

Setup Requirements

1. API Keys Needed

• Google Gemini API: For Gemini 2.5 Pro/Flash models (content generation/writing)
• Groq API (optional): For Kimi-K2-Instruct model (research/writing)
• Serper.dev API: For Google Search (2,500 free searches/month)
• Wavespeed.ai API: For Nano-Banana image generation
• Supabase Account: For database and image storage

2. Supabase Setup

• Create blogs table with fields:
  • title, slug, excerpt, category, tags, featured_image, status, featured, content
• Create storage bucket for blog images
• Configure bucket as public or use signed URLs

3. Workflow Configuration

Update these placeholders:

• RSS Feed URLs: Replace [your website's rss.xml] with your site's RSS feed
• Storage URLs: Update Supabase storage paths in "Upload object" and "Generate presigned URL" nodes
• API Keys: Add your credentials to all HTTP Request nodes
• Niche/Brand: Customize Research Agent system prompt with your industry keywords
• Writing Style: Adjust Writer Agent prompt for your brand voice

Customization Options

Change Image Provider

Replace the "nano banana" node with:

• Gemini Imagen 3/4
• DALL-E 3
• Midjourney API
• Any Wavespeed.ai model

Adjust Schedule

Modify "Schedule Trigger" to run:

• Multiple times daily
• Specific days of week
• On-demand via webhook

Alternative Research Tools

Replace Serper.dev with:

• Perplexity API (included as alternative node)
• Custom web scraping
• Different search providers

Output Format

{
  "title": "Your SEO-Optimized Title",
  "slug": "your-seo-optimized-title",
  "excerpt": "Compelling 2-3 sentence summary with key benefits.",
  "category": "Your Category",
  "tags": ["tag1", "tag2", "tag3", "tag4"],
  "author_name": "Your Team Name",
  "featured": false,
  "status": "draft",
  "content": "<article>...complete HTML with embedded images...</article>"
}

Performance Notes

• Average runtime: 15-25 minutes per blog post
• Cost per post: ~$0.10-0.30 (depending on API usage)
• Image generation: 10-15 seconds per image with Nano-Banana
• Retry logic: Automatically handles API timeouts with 5-15 minute wait periods

Best Practices

1. Review Before Publishing: Workflow saves as "draft" status for human review
2. Monitor API Limits: Track Serper.dev searches and image generation quotas
3. Test Custom Prompts: Adjust Research/Writer prompts to match your brand
4. Image Quality: Review generated images; regenerate if needed
5. SEO Validation: Check slugs and meta descriptions before going live

Workflow Architecture

3 Main Phases:

1. Research → Writer → Image Prompts (Sequential AI Agent chain)
2. Image Generation → Upload → URL Replacement (Loop-based processing)
3. Final Assembly → Database Insert (Single save operation)

Error Handling:

• Wait nodes between agents prevent rate limiting
• Retry logic on agent failures (max 2 retries)
• Conditional checks ensure content quality before proceeding

---

Result: Hands-free blog publishing that maintains quality while saving 3-5 hours per post.