Website Uptime Anomaly Monitor with n8n, Google Sheets & Telegram

Detect website downtime & response-time anomalies automatically—with n8n, Google Sheets, and Telegram

This n8n workflow checks your website every 5 minutes, measures response time, compares it to a rolling average in Google Sheets, and sends instant Telegram + email alerts when your site is down or traffic behavior becomes suspicious.

What this workflow does

• Runs on a schedule: A Schedule Trigger starts the monitoring loop automatically (default: every five minutes).
• Performs an HTTP check: An HTTP Request node tests the target website URL and captures the result, continuing even if the site times out or returns an error.
• Calculates response time: A Code node computes the real response time and normalizes the status code from the check result.
• Compares to a rolling average: The workflow reads recent records from Google Sheets to calculate a rolling average response time.
• Flags two alert conditions:
  • Down condition: non-200 status marks the site as down.
  • Traffic anomaly: response time far above the recent average may indicate issues such as a bot flood or attack.
• Logs every check: Each run is saved to Google Sheets for history and trend tracking.
• Alerts immediately: When an alert condition is met, the workflow sends a Telegram message and an email with the status code, response time, and average for comparison.

Use cases

• SaaS operators monitoring uptime and latency for critical endpoints
• Automation engineers tracking suspected bot-flood or attack impact via response-time spikes
• Teams that want historical reporting in Google Sheets with real-time Telegram/email notifications

Technical details

• n8n nodes/integrations: Schedule Trigger, HTTP Request, Code, Google Sheets (logging + rolling average), Telegram, Email Send, plus if, set, and sticky note components.
• Required Google Sheet headers: checked_at, website_url, status_code, response_time_ms, avg_response_time_ms, is_down, is_traffic_anomaly.