n8n Gmail Trigger: Gemini Email Classify + Auto Reply

Turn new Gmail messages into labeled, AI-classified, ready-to-send replies—automatically

This n8n workflow watches your Gmail inbox, uses Google Gemini to classify every new email (Important, Finance/Billing, Promotion, or Customer Support), applies the matching Gmail label, and generates an AI-written auto reply directly in the original thread.

What this workflow does

• Triggers every minute when a new email arrives in Gmail.
• Extracts the email subject and snippet and sends them to Google Gemini for category classification.
• Applies the corresponding Gmail label (Important, Finance/Billing, Promotion, or Customer Support) to the original message based on the chosen category.
• Routes the email content to a category-specific Google Gemini agent to draft a professional reply tailored to that type of message.
• Replies to the original Gmail thread with the generated response.

Use cases

• SaaS support routing: Automatically identify Customer Support emails and respond faster without manual sorting.
• Billing and finance efficiency: Classify Finance/Billing messages and generate consistent replies for invoicing or payment questions.
• Promotion handling: Tag and respond to promotional inquiries while keeping Important messages prioritized.
• Ops automation for inboxes: Reduce email triage time by labeling and drafting responses based on AI classification.

Technical details

• n8n Gmail Trigger to detect new messages (runs every minute).
• Google Gemini used twice: once for classification (subject/snippet) and once for reply generation via category-specific agents.
• Gmail actions to add labels and reply in the same thread.
• Nodes include: gmail, sticky note, Gmail Trigger, n8n-nodes-langchainagent, n8n-nodes-langchaintext classifier, and n8n-nodes-langchainlm chat google gemini.

Setup requirements

• Connect Gmail OAuth2 credentials with permission to read and reply.
• Connect Google Gemini (PaLM) API credentials for both the classifier and reply-generation agents.
• Create/confirm Gmail labels and update the label IDs in the workflow to match your account.