On-Demand Email Newsletter Summaries from Gmail to Telegram with GPT-4.1-mini

Summary Send a number to your Telegram bot (e.g., 2) and get a neatly formatted digest of all Gmail newsletters received since that date. Each email is summarized by an LLM into concise topics, merged into a single Telegram message, automatically split into chunks to fit Telegram limits, and safely formatted as HTML.

What this workflow does Triggers on your Telegram message containing a number of days, e.g., 1, 2, 7 Fetches all Gmail messages since that date using a custom search query, optionally filtered by senders Retrieves and decodes each email’s HTML, subject, sender name, date Prompts an LLM (GPT‑4.1‑mini) to produce a consistent JSON summary of topics per email Merges topics from all emails into a single digest Builds a readable, enumerated message (with bold titles) Splits it into 3 500‑char parts and sanitizes Markdown to Telegram‑safe HTML Sends the digest to your Telegram chat with preview disabled

Apps and credentials Gmail OAuth2: Gmail account Telegram: Telegram account (bot) OpenAI: OpenAi account

Typical use cases Personal or team daily/weekly newsletter digests in Telegram Curated feeds from selected senders compiled on demand Lightweight knowledge briefings without leaving Telegram

How it works (node-by-node) Telegram Trigger Waits for your message (e.g., "2"). Chat ID is restricted to your Telegram ID for safety. Get days (Code) Takes the numeric daysAgo from the Telegram message text Computes YYYY/MM/DD for Gmail’s after: filter Get many messages (Gmail → getAll, returnAll: true) Uses a custom q filter like: =(from:@.com) OR (from:@.com) OR (from:@.com -"__") after:{{ $json.dateString }} Returns a list of message IDs Loop Over Items (Split in Batches) Iterates through each message ID Get a message (Gmail → get) Retrieves the full message/payload for the current email Get message data (Code) Extracts HTML from Gmail’s payload (body/parts) Normalizes sender to just the name Formats the date as DD.MM.YYYY Passes html, subject, from, date forward Clean (Code) Converts DD.MM.YYYY → MM.DD (for prompt brevity) Passes html, subject, from, date to the LLM Message a model (OpenAI, model: gpt‑4.1‑mini, JSON output) Prompt instructs: Produce JSON: { "topics": [ { "title", "descr", "subject", "from", "date" } ] } Split multi-news blocks into separate topics Combine or ignore specific blocks for particular senders (placeholders __) Keep subject untranslated; other values in __ language Injects subject/from/date/html from the current email Loop Over Items (continues) After all iterations complete, the aggregated per-email results are available Merge (Code) Flattens the topics arrays from all processed emails into one combined topics list Create TG message (Code) Renders an enumerated list: 1. Title (bold) Short description Original subject From — Date Split (Code) Splits into 3 500‑character chunks to stay below Telegram’s 4 096 limit with HTML overhead Sanitize (Code) Escapes &, <, > Fixes unbalanced * and _ Converts basic Markdown markers to Telegram HTML Send a message (Telegram) Sends each part with parse_mode=HTML, previews disabled

Node map | Node | Type | Purpose | |---|---|---| | Telegram Trigger | Trigger | Receive daysAgo command from Telegram | | Get days | Code | Compute Gmail after:YYYY/MM/DD from daysAgo | | Get many messages | Gmail (getAll) | Search emails since date with custom from: filters | | Loop Over Items | Split in Batches | Iterate messages one-by-one | | Get a message | Gmail (get) | Fetch full message payload | | Get message data | Code | Extract HTML/subject/from/date; normalize sender and date | | Clean | Code | Reformat date and forward fields to LLM | | Message a model | OpenAI | Summarize email into JSON topics | | Merge | Code | Merge topics from all emails | | Create TG message | Code | Build human-friendly digest text | | Split | Code | Chunk into 3 500‑char parts | | Sanitize | Code | Escape HTML and map Markdown to Telegram HTML | | Send a message | Telegram | Deliver digest to Telegram chat |

Before you start Create a Telegram bot and get its token (via @BotFather) Get your Telegram user ID to restrict access Connect Gmail OAuth2 in n8n Add your OpenAI API key Import the provided workflow JSON into n8n

Setup instructions

1. Telegram Telegram Trigger node: additionalFields.chatIds = your Telegram user ID Send a message node: chatId = your Telegram user ID parse_mode = HTML disable_web_page_preview = true

2. Gmail Connect a Gmail OAuth2 credential (Gmail account) In Get many messages, adjust filters.q to your senders and rules: Example: =(from:news@publisher.com) OR (from:briefs@media.com -"promo") after:{{ $json.dateString }} If needed, add label: or category: filters

3. OpenAI Message a model: Model: gpt‑4.1‑mini (can swap to gpt‑4o‑mini or your preferred) Update the prompt placeholders: __ language → your target language __ sender rules → your special cases (combine blocks, ignore sections)

4. Safety and formatting Keep parse_mode=HTML in Telegram The Sanitize node is designed for and only; avoid other HTML tags The Split node uses 3 500 chars per part to stay safe under Telegram limits

How to use In Telegram, send a number indicating “days ago” Example: 2 → will query Gmail after the date 2 days ago The workflow compiles and returns a digest in your chat Rerun anytime with a new number

Customization ideas Labels instead of global search: q = label:Newsletters after:{{ $json.dateString }} Time window control: add before: or exact date ranges Different language: set the __ language in the LLM prompt Model choice: swap to cheaper/faster models if volume is high Chunk size: adjust from 3 500 to your needs Formatting: tweak Create TG message to include links parsed from HTML (if you add an HTML parser step)

Limits and notes Telegram messages are limited to ~4 096 characters; we chunk to 3 500 per part Gmail “after:” uses YYYY/MM/DD and Google’s interpretation of dates; your n8n server time influences the computed date LLM usage incurs cost and latency proportional to email size and count HTML extraction is robust for typical Gmail structures but may need tweaks for exotic MIME layouts

Privacy and safety Emails are sent to OpenAI for summarization—ensure that’s acceptable for your data policies The Telegram Trigger restricts chat access; keep your chatIds locked down Avoid sending raw HTML to Telegram; rely on the Sanitize node

Sample output format (Telegram) Bold topic title

One-sentence description

Original Subject Line → Sender Name — DD.MM.YYYY

Next topic title

...

Tips and troubleshooting Got empty digests? Check Gmail filters.q and make sure there really are emails after the computed date Model errors or empty JSON? Lower prompt complexity or switch model HTML formatting issues in Telegram? Ensure parse_mode=HTML and keep only , Long messages not fully delivered? Reduce chunk size from 3 500

Tags gmail, telegram, openai, llm, newsletters, digest, summarization, automation

Changelog v1: Initial release with sender filters, topic merging, Telegram HTML sanitization, and on-demand time window via Telegram message