Gmail AI Email Classifier & Auto-Reply with Sheets Logging

Instant Gmail triage + AI replies, with Google Sheets logging

This n8n workflow monitors your Gmail for new emails every minute, uses OpenAI to classify priority and draft a response, and then automatically replies—or routes urgent messages for human approval—while logging everything to Google Sheets for easy tracking.

What this workflow does

• Gmail Trigger (runs every minute): Detects newly arrived emails in your Gmail inbox.
• OpenAI-powered classification & drafting: Sends the email subject to an OpenAI chat model to:
  • categorize the message
  • set priority
  • decide whether a reply is needed
  • draft a response in a structured format
• Routing rules for auto-reply vs approval: Uses rules to ignore newsletters/spam (or emails that don’t need a reply). For high/urgent messages, it requests human approval; otherwise, it proceeds with auto-reply.
• Human-in-the-loop for urgent emails: Sends an approval request email via Gmail and waits for the reviewer’s response before continuing.
• Send the reply in Gmail: Replies to the original message using the AI-generated response.
• Log to Google Sheets: Appends a row to Google Sheets containing the processed email and its AI-generated metadata.

Use cases

• SaaS operators who want consistent, fast responses to incoming support-related emails—without manually triaging every message.
• Teams that handle urgent requests with a reviewer approval step while auto-replying everything else.
• Automation engineers who need a clear audit trail of AI email classification and drafted replies in Google Sheets.

Technical details

• n8n Cloud or self-hosted n8n
• Gmail: Gmail Trigger + Gmail send/reply steps (OAuth2 credentials required)
• OpenAI: OpenAI Chat Model node for classification, priority decision, and drafted reply content
• Switch logic: Routes messages based on priority/reply-needed decisions
• Google Sheets: Appends processed email data and AI metadata to the selected spreadsheet/sheet
• Extras: Includes code and sticky note nodes to support workflow logic and configuration

Setup reminder: configure Gmail OAuth2, add OpenAI API credentials, connect Google Sheets, and set the approval request recipient/message to match your human review workflow.