Have thousands of unlabeled historical emails? This tutorial shows how to build a retroactive Gmail labeling workflow in Needle that bulk-organizes your past emails with AI.

Overview

The workflow scans your existing Gmail archive, applies intelligent labels to historical messages, and organizes years of email history—turning email chaos into a searchable, organized system.

Key Actions

1. Gmail Archive Scanner – Retrieves historical emails (last 30 days, 90 days, or custom range)
2. AI Content Analysis – Examines subject, sender, body, and context for each email
3. Smart Label Assignment – Determines appropriate labels based on patterns
4. Batch Label Application – Applies labels to hundreds of emails simultaneously
5. Progress Tracking – Reports how many emails were labeled and which categories created

What You'll Need

• Gmail Account – Personal or Google Workspace Tip: Start with a limited date range (e.g., last 30 days) to test before running on entire archive
• Label Categories – Predefined label structure (e.g., Projects, Clients, Finance, Personal)
• Processing Limit – Set batch size to avoid Gmail API rate limits (e.g., 100 emails per run)

How It Works

1. You configure the date range for retroactive labeling (e.g., emails from Jan 1 - March 31, 2025)
2. The workflow retrieves emails in batches (e.g., 100 at a time)
3. For each email, AI analyzes:
   • Sender domain and name
   • Subject line patterns
   • Email body keywords
   • Previous manual labels (if any)
4. Labels are assigned based on rules like:
   • Invoices →

     💰 Finance/Invoices

   • Meeting invites →

     📅 Calendar/Meetings

   • Client emails →

     👥 Clients/[ClientName]

   • Newsletters →

     📧 Newsletters

5. Labels are applied in bulk via Gmail API
6. Summary report shows:
   • Total emails processed
   • Labels created
   • Labels applied
   • Emails that couldn't be categorized

Wrap-up

With this Needle workflow, you can finally organize years of email history without manual effort—perfect for professionals switching to a label-based email system, consultants managing client communications, and anyone with email overwhelm.