n8n API Uptime Monitor: Google Sheets Logs & Slack Alerts

Keep your APIs under control with automated uptime checks, Google Sheets logs, and Slack outage alerts

This n8n workflow monitors a list of API endpoints on a schedule, measures response time, validates basic health, logs every check to Google Sheets, and sends Slack alerts when outages begin—then posts recovery messages when services come back.

What this workflow does

• Runs on a schedule: Starts a monitoring cycle at your chosen interval.
• Checks configured endpoints: Loads a predefined API list (API name, URL, and thresholds) and performs an HTTP GET request for each.
• Measures and evaluates health: Tracks request duration, checks HTTP status code, and applies basic response-body validation to determine whether the endpoint is healthy.
• Logs results to Google Sheets: Appends each check outcome (API, timestamp, status code, response time) into your log sheet.
• Detects and de-duplicates outages: For unhealthy checks, it builds an incident payload and checks the “Active Alerts” Google Sheets sheet to avoid duplicate notifications.
• Alerts in Slack only when needed: Sends a Slack alert for a new incident if no active alert exists; stores the active incident in Google Sheets.
• Sends recovery notifications: For healthy checks, it looks for an existing active alert and—if found—sends a Slack recovery message and marks the alert inactive in Google Sheets.

Use cases

• Monitor critical SaaS backend APIs and catch uptime issues early.
• Provide operations teams with clear Slack updates and an auditable Google Sheets history.
• Track incidents across multiple endpoints without spamming Slack with duplicate alerts.

Technical details

• Google Sheets (OAuth): logs results and manages active incident state via an “Active Alerts” sheet.
• Slack: posts outage and recovery notifications to a selected channel.
• Workflow logic uses nodes such as if, set, code, slack, split out, and sticky note to control alerting behavior and messaging.

Setup note: Add Google Sheets credentials, specify the target spreadsheet and required sheets/columns, add Slack credentials and channel, then update the API list (URLs and thresholds) and schedule interval.