Gmail AI Email Classifier: OpenAI + Airtable + Sheets in n8n

Automatically classify incoming Gmail emails with OpenAI—and respond using your FAQ

This Gmail AI Email Classifier workflow in n8n monitors unread Gmail messages, uses OpenAI to categorize them, logs results to Google Sheets and Airtable, and generates an FAQ-grounded reply before responding in the original email thread—while notifying your Slack channel.

What this workflow does

• Checks Gmail every minute for new unread messages and triggers when an unread email arrives.
• Extracts sender details (sender name and email address) and formats the email snippet/subject.
• Classifies the email with OpenAI into a predefined category, then routes the message based on that classification.
• Logs every email outcome to Google Sheets (“Email Logs”) and Airtable (email details + category).
• Sends unclear results to Manual Review by writing unmatched/fallback classifications to a separate Google Sheets tab (“Manual Review”) with a Needs Review status.
• Generates a reply from your FAQ by retrieving a relevant FAQ entry from a Supabase vector store and having OpenAI draft a response using only that FAQ content.
• Replies to the Gmail thread after a short wait, then posts a notification to Slack.

Use cases

• Route support inquiries by category and track them in Google Sheets/Airtable.
• Auto-reply with consistent, FAQ-based responses for common questions.
• Flag low-confidence or unmatched emails for human follow-up via “Manual Review”.
• Keep your team informed in Slack whenever a new classified email is handled.

Technical details

• n8n trigger: Gmail unread email polling (every minute)
• OpenAI: classification + reply generation (with embeddings for retrieval)
• Supabase: vector search against company_docs / match_company_docs for FAQ retrieval
• Logging: Google Sheets (“Email Logs”, “Manual Review”) + Airtable table writes
• Communication: Gmail reply + Slack notification
• Workflow nodes mentioned: set, no op, wait, gmail, merge, slack

Designed for n8n users, automation engineers, and SaaS operators who want a reliable Gmail AI email classifier that’s auditable (Sheets/Airtable) and grounded in documented FAQ content (Supabase + OpenAI).