Gmail Email Classifier with GPT-4 Auto-Generated Draft Replies

How It Works This workflow automatically classifies incoming Gmail messages into categories such as High Priority, Inquiry, and Finance/Billing, and then generates professional draft replies using GPT-4. By combining Gmail integration with AI-powered text generation, the workflow helps business owners and freelancers reduce the time spent managing emails while ensuring that important messages are handled quickly and consistently.

When a new email arrives, the workflow: Triggers via Gmail. Uses an AI classifier to categorize the message. Applies the appropriate Gmail label. Passes the email body to GPT-4 to generate a tailored draft reply. Saves the draft in Gmail, ready for review and sending.

Requirements A Gmail account with API access enabled.
An OpenAI API key with GPT-4 access.
n8n account or self-hosted instance.

Setup Instructions Import this workflow into your n8n instance.
Under Credentials, connect your Gmail account and OpenAI API key.
Replace placeholder YOUR_LABEL_ID_XXX values with your Gmail label IDs (obtainable via Gmail → List Labels).
Execute the workflow and check that draft replies are generated in your Gmail account.

Customization Add or edit categories to fit your business needs (e.g., “Sales Leads” or “Support”).
Adjust the GPT-4 prompts inside each “Generate Draft” node to match your preferred tone and style.
Combine with other workflows (e.g., CRM integration, Slack alerts) for a complete email automation system.

This template is especially useful for small businesses and freelancers who want to save time, improve response speed, and maintain professional communication without manually writing every reply.