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

Nodes

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

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

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

Gmail

Connect a Gmail OAuth2 credential (Gmail account)
In Get many messages, adjust filters.q to your senders and rules:
- Example: =(from:[email protected]) OR (from:[email protected] -"promo") after:{{ $json.dateString }}
If needed, add label: or category: filters

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)

Safety and formatting

Keep parse_mode=HTML in Telegram
The Sanitize node is designed for <b> and <i> 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 <b>, <i>
Long messages not fully delivered? Reduce chunk size from 3 500