n8n HTTPS Website Monitoring: Google Sheets to Slack & Gmail Alerts

Weekly HTTPS & Certificate Monitoring with Google Sheets → Slack + Gmail Alerts

This n8n workflow checks the HTTPS reachability and TLS certificate status of your client websites from a Google Sheets list—then automatically logs results back to the sheet and sends Slack and Gmail alerts when problems appear or persist.

What this workflow does

• Schedules or manual runs: executes every Monday at 08:00 (or when you trigger it manually).
• Loads alert settings: reads thresholds and the digest email address from your configuration.
• Reads websites from Google Sheets: keeps only rows where website is non-empty and not marked inactive (e.g., active set to “no”).
• Checks HTTPS + certificate health via weio.ai: calls the weio.ai HTTPS check API for each website (batched one at a time with a delay) to evaluate reachability, HTTPS redirect behavior, and certificate validity/expiry.
• Classifies severity: maps each result to ok, warning, or critical, compares against the previous status stored in the sheet, and timestamps the check.
• Writes back to Google Sheets: updates the matching rows with severity, HTTPS status, detailed info, certificate expiry, and checked_at.
• Alerts on changes: sends an urgent Slack message for any critical issue that is new or changed since the last run; sends a single Gmail digest listing all non-ok sites.
• Error handling: if execution fails, posts an error notification to Slack using an Error Trigger.

Use cases

• SaaS operators monitoring customer sites for HTTPS downtime, redirect issues, or certificate expiry.
• Automation engineers centralizing website security checks into Google Sheets with Slack/Gmail notifications.
• Weekly reporting workflows for managed services teams.

Technical details

• Integrations: Google Sheets, Slack, Gmail, and weio.ai.
• n8n nodes mentioned: if, set, code, gmail, slack, filter.