Create AI newsletters from YouTube with LangChain, Gemini, Apify & Gmail

Video → Newsletter AI Agent

This n8n workflow converts a YouTube video into a polished, email-ready newsletter. It scrapes the transcript, extracts a thumbnail/logo and brand color theme, uses multiple AI agents to (1) clean & summarize the transcript into three newsletter sections, (2) convert that content into a styled HTML newsletter (color-aware), then saves the draft to Google Sheets and sends the email to subscribers via Gmail. The flow is optimized for batch sending and brand-consistent HTML output.

How it works (step-by-step) 1. Trigger — On form submission accepts Brand Name, Brand Website, and YouTube video link. 2. Site scrape & colour study — HTTP requests + Information Extractor → AI agent derives brand color theme (primary/secondary/accent/background). 3. Transcript retrieval — Two YouTube transcript scrapers (Apify acts) fetch the video transcript and thumbnail; a small Code node merges transcript chunks. 4. Summarization & journalism — AI Agent2 (LangChain/Gemini) cleans the transcript, extracts thesis + key points, and writes 3 newsletter sections in a journalistic tone. 5. HTML conversion — Convert Newsletter to HTML (AI) agent applies the fixed layout and injects only text color variables (keeps layout intact) and outputs Subject + HTML body (≤1000 words). 6. Aggregate & merge — Merge + Aggregate assemble files, assets, and parsed outputs. 7. Save & send — Save the email draft to Google Sheets (Save Newsletter Draft in Google Sheet) and loop through subscribers from a subscribers sheet; Sending Emails to all the Subscribers (Gmail node) sends the HTML to each address in batches. 8. Batching & looping — Split In Batches handles large subscriber lists; Loop Over Items triggers the HTML-conversion per recipient batch.

Quick Setup Guide 👉 [Demo & Setup Video](https://drive.google.com/file/d/1bOfkyDY-Y06pq9ojZzLaGy5Xuvp9LdH7/view?usp=sharing) 👉 [Sheet Template](https://docs.google.com/spreadsheets/d/1hvB5Zif52eCLvX7EOifQv9OI5usn-CQ50-TsZTMQA/edit?usp=sharing) 👉 [Course](https://www.udemy.com/course/n8n-automation-mastery-build-ai-powered-enterprise-ready/?referralCode=2EAE71591D3BEB80F2CC)

Nodes of interest - On form submission (formTrigger) — entry point for video + brand inputs. - You Tube Transcript Scraper, You Tube Transcript Scraper1 (HTTP Request → Apify) — transcript + thumbnail fetching. - Information Extractor & AI Agent1 — website color/theme extraction. - Code in JavaScript — merges transcript pieces into a single text payload. - AI Agent2 (LangChain agent + Gemini Chat Model) — transcript → journalist-style newsletter sections. - Convert Newsletter to HTML (AI) (LangChain agent + Structured Output Parser) — builds constrained, brand-aware HTML email and subject. - Structured Output Parser1/2 — enforce schemas for color theme / structured outputs. - Get row(s) in sheet & Save Newsletter Draft in Google Sheet (Google Sheets) — subscriber list + draft storage. - Loop Over Items / Split In Batches — batch processing for sends. - Sending Emails to all the Subscribers (Gmail) — SMTP/OAuth send. - OpenRouter Chat Model — LM compute provider configured in the workflow.

What you’ll need (credentials & resources) - Google Sheets OAuth2 (for reading subscribers & saving drafts). - Gmail OAuth2 (for sending HTML emails). - Gemini / LLM provider credentials (Gemini API key or equivalent) for the LangChain agents. - Apify API key (for the YouTube transcript scrapers). - ConvertAPI (or similar) key if you convert logos (SVG→PNG) server-side. - Host storage / publicly accessible URLs for images (thumbnails, logos) or a file-store (S3). - Optional: SendGrid / Mailgun credentials if you swap Gmail for a transactional email provider. Security note: do NOT hardcode credentials in node parameters; use n8n credentials manager or environment variables.

Recommended settings & best practices - Batch size & rate-limits: set Split In Batches to a conservative batch size (e.g., 50–200) and add delays between batches to avoid provider rate limits and Gmail throttling. - Retries & timeouts: enable retries for HTTP Request nodes and set sensible timeouts (e.g., 30–60s). Use exponential backoff. - LM controls: set token/response length limits and maxoutputtokens (or equivalent) to avoid runaway costs; enforce the 1000-word HTML hard limit in the prompt. - Validation: validate the YouTube URL and that transcript content exists before invoking AI summarization (fail fast with a clear error). - Schema enforcement: use Structured Output Parser nodes with strict JSON schemas to prevent malformed outputs. - Testing: run with a small subscriber test sheet and use a safety test Gmail account before sending to production lists. - Logging & monitoring: log each run (video URL, subject, send count, errors) to a monitoring sheet or external logging service. - Privacy & compliance: ensure recipients have consent to receive emails (store opt-ins); include unsubscribe handling if you move beyond one-off sends. Comply with CAN-SPAM / local laws. - Credential rotation: rotate API keys periodically and revoke compromised tokens. - Content safety: instruct the LM agents to avoid hallucinated citations — only include links you can verify.

Customization ideas - Multi-language support: auto-detect video language and run summarizer in that language. - A/B subject testing: generate 2–3 subject lines and send variations to subsets. - Scheduling: add a scheduler node to delay sends or publish at optimal send-times per recipient timezone. - Integrate with SendGrid/Mailgun for higher throughput and analytics (opens/clicks). - Add personalization tokens (first name, company) from subscribers sheet to the HTML (merge fields). - Auto-attach transcript as plain-text footer or include “Read more” link to a hosted full article. - Add analytics: record opens, clicks, and engagement back into Google Sheets or a database. - Support other platforms: ingest videos from Vimeo, Loom, or uploaded MP4s. - Use a templating engine to allow multiple newsletter layouts and style variants. - Auto-generate social posts (Twitter/X, LinkedIn) from the newsletter summary.