n8n Google Sheets Watcher: Gemini + Telegram Alerts

Detect real changes in your Google Sheets URL watchlist—and alert via Telegram

This n8n workflow watches Google Sheets URLs every 10 minutes, checks each page for meaningful content changes using Google Gemini, and sends Telegram alerts only when something actually changed (while suppressing noisy, meaningless updates).

What this workflow does

• Runs on a schedule (every 10 minutes) to keep your watchlist continuously monitored.
• Reads a Google Sheets watchlist and filters to rows marked active (TRUE/FALSE).
• Downloads each URL page over HTTP and extracts the visible body text.
• Cleans “noisy” dynamic text (e.g., timestamps, counters, UUIDs, long tokens) and can optionally narrow to sentences containing a configured keyword.
• Generates a hash of the cleaned text and compares it to the previous hash stored in Google Sheets to classify: first run, changed, unchanged, or error.
• Uses Google Gemini for change detection: when the page changed, Gemini receives the old and new snapshots to summarize what actually changed.
• Suppresses irrelevant alerts when Gemini returns “NO MEANINGFUL CHANGE”.
• Sends Telegram alerts with the meaningful change summary and updates Google Sheets with the latest hash, snapshot, last checked time, and last change summary (or saves a baseline on first run).

Use cases

• SaaS operators monitoring public pricing pages or announcements listed in a Google Sheets watchlist.
• Automation engineers tracking specific keyword-relevant updates on multiple URLs.
• Teams receiving Telegram notifications only for real content changes—without being spammed by timestamps, counters, or session noise.

Technical details

• Google Sheets (watchlist + storing last_hash, last_snapshot, last_checked, last_change, and a row_number key for updates)
• Google Gemini to summarize differences and determine meaningful change vs “NO MEANINGFUL CHANGE”
• Telegram for alert delivery
• n8n nodes include: if, set, html, no op, crypto, filter (plus HTTP/page retrieval as part of the check)
• Setup: configure Google Sheets Service Account credentials in n8n