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.

💡 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)

🛠 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

🧩 How it works (high-level) Manual Trigger → Get many posts (from subreddit)
Select Top 10 (Code node, ranking by ups + comments + date)
Set topic of interest → AI filter → String to JSON → If topic of interest
Loop Over Items for each valid post
Fetch post comments → Clean comments (Code) → Merge comments → Merge with post
Summarize post + comments (AI) → Merge summaries → Create newsletter HTML
Send Gmail message with the generated HTML

⚙️ 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

✨ 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

🧠 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

🧭 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

📬 Contact & Feedback Need help tailoring this workflow to your stack?

📩 Luis.acosta@news2podcast.com
🐦 @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.