Website Uptime Monitor (n8n): Google Sheets + Slack Alerts

Keep your websites online—automatically monitor uptime and alert your team

This n8n workflow checks your monitored websites every 10 minutes, classifies each result as UP, SLOW, or DOWN, and sends real-time incident and recovery notifications to Slack (with optional Gmail email alerts). It also logs downtime history to Google Sheets and posts a daily Slack digest.

What this workflow does

• Runs every 10 minutes and reads the site list from the Google Sheets “Sites” tab.
• Filters out inactive/blank rows, then normalizes and deduplicates URLs before testing.
• For each site, performs an HTTP request, measures response time, and evaluates results against configured expectations (expected HTTP status, optional page keyword, and maximum response time).
• Determines the check outcome (UP, SLOW, or DOWN) and records the reason.
• Consults the previous state in Google Sheets “Site State”, and only opens an incident after a configured number of consecutive failures.
• Sends Slack alerts for incident open, recovery, and scheduled 6-hour reminders while the incident remains active.
• On recovery, appends a closed-incident entry to “Incident History” with incident start, recovery time, duration, and last reason.
• Updates “Site State” on every run with latest status, counters, timestamps, and last check details.
• Runs daily at 09:00 to generate a summary from the last 24 hours of incident history and posts a daily Slack digest.
• If the workflow errors, triggers a crash alert to Slack.

Use cases

• SaaS operators who need automated website uptime monitoring with concise Slack notifications.
• Automation engineers maintaining multiple public endpoints and tracking downtime history in Google Sheets.
• Teams that want both incident reminders and a daily operational digest without manual reporting.

Technical details

• Google Sheets: reads Sites, writes Site State, appends to Incident History
• HTTP Request: checks each URL and measures response time
• Slack: incident open, recovery, 6-hour reminders, daily digest, and crash alerts
• Optional Gmail: email alerts alongside Slack
• n8n nodes used: if, code, gmail, slack, sticky note, http request