n8n Workflow: Gemini URL Checks from Google Sheets + Gmail Alerts

Monitor URLs in Google Sheets hourly—and alert your inbox only when Gemini confirms a condition

This n8n workflow watches URLs you track in Google Sheets, fetches each page (HTTP with Airtop browser fallback), asks Google Gemini to evaluate your plain-language condition with quoted evidence, logs every result back to Sheets, and sends a Gmail alert exactly when the condition becomes true.

What this workflow does

• Hourly scheduling: Runs every hour, loads the Watchlist tab, and selects only rows whose next check is due (up to your configured per-run limit).
• URL retrieval with smart fallback: Attempts each target URL via HTTP first. If the site blocks requests or the content is too short / JavaScript-rendered, it automatically switches to an Airtop browser session to load the page.
• Optional page interaction + extraction: If configured, the workflow clicks an “open step” element, waits for the page to update, and extracts readable page text.
• Gemini-based condition checking: Sends the extracted page text and the row’s condition to Google Gemini, which returns a YES/NO/UNCLEAR verdict, a confidence score, and exact quotes as evidence.
• Evidence validation + notification logic: Validates Gemini’s evidence against the page text and uses a state machine to decide when to notify (e.g., only when a previously NO watch turns to YES, or after repeated monitoring errors).
• Updates Sheets + writes logs: Updates Watchlist fields (streaks, errors, next_due_at, last evidence/error) and appends a record to the Log tab.
• Sends email alerts: Sends a Gmail email to the row’s notify_to address (or a default) only when notification is required.

Use cases

• Track product pages or announcements and alert when a specific requirement appears.
• Monitor policy pages or changelogs for a “true” condition with sourced quotes.
• Quality-monitor SaaS pages where content loads via JavaScript and needs browser fallback.

Technical details

• Integrations: Google Sheets (Watchlist + Log), Gmail, Google Gemini, Airtop (browser automation).
• n8n nodes/tools mentioned: if, set, code, no op, wait, gmail (as part of the workflow logic).
• Workflow model: hourly checks, HTTP-to-Airtop fallback, Gemini evidence + state-machine notification, and persistent logging to Sheets.

Setup: Create a Google Sheet with Watchlist and Log tab, then configure the columns/rows for URLs, conditions, notify targets, and check timing.