Gmail Triage n8n Workflow: Label Unread Emails w/ Gemini 3.5

Automatically triage your Gmail unread emails—then label and “process” them with Gemini (via OpenRouter)

This Gmail Triage n8n Workflow polls your inbox for unread messages, sends the sender/subject/body to Gemini 3.5 through OpenRouter for structured classification, and then applies the matching Gmail label while marking the email as read—so your team’s inbox stays clean and organized.

What this workflow does

• Polls Gmail every minute and checks for up to 50 unread emails (excluding drafts).
• Extracts and normalizes safe fields from each email, including sender, subject, plain-text body, and timestamps.
• Uses OpenRouter (Gemini) with a strict JSON schema to classify each message (e.g., category, priority, language, confidence, plus a short summary).
• Validates the AI response; if the output is invalid, the workflow run fails.
• Loads your existing Gmail labels and resolves the correct “AI Triage/…” label ID for the predicted category.
• Applies the label to the message and removes the UNREAD label to mark it as processed.

Use cases

• Route inbound sales: label New lead vs. Existing client automatically.
• Invoice triage: quickly tag Invoice emails for accounting workflows.
• Vendor/sponsor screening: classify Vendor pitch and reduce manual sorting.
• Inbox hygiene: apply Spam label and move on after processing.

Technical details

• n8n nodes / stack: code, gmail, sticky note, http request, gmail trigger.
• Gmail integration: OAuth2 credential, label lookup, label application, and UNREAD removal.
• AI integration: OpenRouter via HTTP Request using a header-auth API key (Gemini 3.5).
• Required labels (create exactly): “AI Triage/New lead”, “AI Triage/Existing client”, “AI Triage/Pricing”, “AI Triage/Invoice”, “AI Triage/Vendor pitch”, “AI Triage/Spam”.

Ideal for: n8n users, automation engineers, and SaaS operators who want reliable Gmail triage automation with AI-powered labeling.