n8n Gmail OOO Critical Email Routing with Gemini & Slack

Gmail Out-of-Office? Route only truly critical emails automatically with Gemini, Slack, Sheets, and labels.

This n8n workflow monitors your Gmail inbox during out-of-office coverage, uses Google Gemini to classify whether each new unread message is critical, then escalates critical emails to your backup via Slack—with an automatic Gmail reply, a Google Sheets audit log, and a Gmail label. Non-critical messages require no further action.

What this workflow does

• Triggers every minute when a new unread Gmail email arrives (excluding Promotions and Social categories).
• Extracts key email fields such as sender, subject, snippet, message ID, and thread ID, then loads out-of-office routing settings.
• Sends the email details to the Google Gemini API (generateContent) and parses the JSON response for:
  • critical vs. non-critical decision
  • category and urgency reason
  • a Slack-ready escalation summary
• If the email is critical, posts an escalation message to a specified Slack channel and mentions the designated backup person.
• Replies to the sender in Gmail with an out-of-office message that includes the backup contact.
• Logs escalation details to Google Sheets and labels the original Gmail message for traceability.
• If the email is not critical, it takes no further action.

Use cases

• SaaS operators and founders covering support/responding while away—only urgent customer or incident emails trigger backup escalation.
• Automation engineers who want an auditable workflow combining Gmail, Gemini, Slack, and Google Sheets.
• Teams needing consistent out-of-office handling without manually triaging every inbox message.

Technical details

• n8n nodes/workflow logic: Trigger (Gmail), if, set, no op, Gmail, Slack, Sticky Note
• Uses Gmail OAuth2 for inbox trigger, reply, and label actions.
• Uses Google Gemini (PaLM) credentials via an HTTP request to the generateContent endpoint.
• Uses Slack OAuth with configured channel ID and backup user ID for mentions.