Create Curated Newsletters from Reddit Discussions with GPT-4o Mini and Gmail

📰 Reddit to Newsletter (Automated Curation with Open AI 4o Mini )

Turn the best posts from a subreddit into a ready-to-send HTML newsletter — no copy-pasting, no wasted time.
This workflow fetches new posts, filters by topic of interest, analyzes comments, summarizes insights, and composes a clean HTML email delivered straight to your inbox with Gmail.

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💡 What this workflow does

• ✅ Fetches posts from your chosen subreddit (default: r/microsaas, sorted by “new”)
• 🏆 Selects the Top 10 by upvotes, comments, and recency
• 🧭 Defines a topic of interest and runs a lightweight AI filter (true/false) without altering the original JSON
• 💬 Pulls and flattens comments into a clean, structured list
• 🧠 Summarizes each post + comments into main_post_summary, comment_insights, and key_learnings
• ✍️ Generates a newsletter in HTML (not Markdown) with headline, outline, sections per post, quotes, and “by the numbers”
• 📤 Sends the HTML email via Gmail with subject “Reddit Digest” (editable)

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🛠 What you’ll need

• 🔑 Reddit OAuth2 connected in n8n
• 🔑 OpenAI API key (e.g., gpt-4o-mini) for filtering and summarization
• 🔑 Gmail OAuth2 to deliver the newsletter
• 🧵 A target subreddit and a clearly defined topic of interest

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🧩 How it works (high-level)

1. Manual Trigger → Get many posts (from subreddit)
2. Select Top 10 (Code node, ranking by ups + comments + date)
3. Set topic of interest → AI filter → String to JSON → If topic of interest
4. Loop Over Items for each valid post
5. Fetch post comments → Clean comments (Code) → Merge comments → Merge with post
6. Summarize post + comments (AI) → Merge summaries → Create newsletter HTML
7. Send Gmail message with the generated HTML

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⚙️ Key fields to adjust

• Subreddit name and “new” filter in Get many posts
• Ranking logic inside Top 10 Code node
• Text inside Set topic of interest
• Prompts for AI filter, Summarize, and Create newsletter (tone & structure)
• Recipient & subject line in Send Gmail message

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✨ Use cases

• Weekly digest of your niche community
• Podcast or newsletter prep with community insights
• Monitoring specific themes (e.g., “how to get first customers”) and delivering insights to a team or client

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🧠 Tips & gotchas

• ⏱️ Reddit API limits: tune batch size and rate if the subreddit is very active
• 🧹 Robust JSON parsing: the String to JSON node handles clean, fenced, or escaped JSON; failures return error + raw for debugging
• 📨 Email client quirks: test long newsletters; some clients clip lengthy HTML
• 💸 AI cost: the two-step (summarization + HTML generation) improves quality but can be merged to reduce cost

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🧭 Quick customization

• Change microsaas to your target subreddit
• Rewrite the topic of interest (e.g., “growth strategies”, “fundraising”, etc.)
• Adapt the newsletter outline prompt for a different tone/format
• Schedule with a Cron node for daily or weekly digests

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📬 Contact & Feedback

Need help tailoring this workflow to your stack?

📩 [email protected]
🐦 @guanchehacker

If you’re building something more advanced with curation + AI (like turning the digest into a podcast or video), let’s connect — I may have the missing piece you need.