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Build Gmail Contact Database with GPT-5 Nano, Brave Search & Google Sheets

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Created by: Václav Čikl || venca

Václav Čikl

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Last update 2 hours ago

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Overview

Transform your Gmail sent folder into a comprehensive, enriched contact database automatically. This workflow processes hundreds or thousands of sent emails, extracting and enriching contact information using AI and web search – saving days of manual work.

What This Workflow Does

  1. Loads sent Gmail messages and extracts basic contact information
  2. Deduplicates contacts against your existing Google Sheets database
  3. Searches for email conversation history with each contact
  4. AI-powered extraction from email threads (phone, socials, websites)
  5. Fallback web search via Brave API when no email history exists
  6. Saves enriched data to Google Sheets with all discovered contact details

Perfect For

  • Musicians & bands organizing booker/venue contacts
  • Freelancers & agencies building client databases
  • Sales teams enriching prospect lists from outbound campaigns
  • Consultants creating structured contact databases from years of emails

Key Features

Intelligent Two-Path Enrichment

  • Path A (Email History): Analyzes existing email threads to extract contact details from signatures and message content
  • Path B (Web Search): Falls back to Brave API search + HTML scraping when no email history exists

AI-Powered Data Extraction

Uses GPT-5 Nano to intelligently parse:

  • Phone numbers
  • Website URLs
  • LinkedIn profiles
  • Instagram, Twitter, Facebook, Youtube, TikTok, LinkTree, BandCamp...
  • Alternative email addresses

Built-in Deduplication

Prevents duplicate entries by checking existing Google Sheets records before processing.

Free-Tier Friendly

Runs entirely on free tiers:

  • Gmail API (free)
  • OpenAI GPT-5 Nano (cost-effective)
  • Brave Search API (2,000 free searches/month)
  • Google Sheets (free)

Setup Requirements

Required Accounts & Credentials

  1. Gmail Account - OAuth2 credentials for Gmail API access
  2. OpenAI API Key - For GPT-5 Nano model
  3. Brave Search API Key - Free tier (2,000 searches/month)
  4. Google Sheets - OAuth2 credentials

Google Sheets Structure

Create a Google Sheet with these columns (see template link):

Template Sheet: Make a copy here

How to Use

  1. Clone this workflow to your n8n instance
  2. Configure credentials for Gmail, OpenAI, Brave Search, and Google Sheets
  3. Create/connect your Google Sheet using the template structure
  4. Run manually to process all sent emails and build your initial database
  5. Review results in Google Sheets - enriched with discovered contact info

First Run Tips

  • Start with a smaller Gmail query (e.g., last 6 months) to test
  • Check Brave API quota before processing large volumes
  • Manual trigger means you control when processing happens
  • Processing time varies based on email volume (typically 2-5 seconds per contact)

Customization Ideas

Extend the Enrichment

  • Include company information parsing
  • Extract job titles from email signatures

Automate Regular Updates

  • Convert manual trigger to scheduled trigger
  • Process only recent sent emails for incremental updates
  • Add email notification when new contacts are added

Integration Options

  • Push enriched contacts to CRM (HubSpot, Salesforce)
  • Send Slack notifications for high-value contacts
  • Export to Airtable for relational database features

Improve Accuracy

  • Add human-in-the-loop review for uncertain extractions
  • Implement confidence scoring for AI-extracted data
  • Add validation checks for phone numbers and URLs

Use Case Example

Music Promoter Building Venue Database:

  • Processed 1,835 sent emails to bookers and venues
  • AI extracted contact details from 60% via email signatures
  • Brave search found websites for remaining 40%
  • Final database: 1,835 enriched contacts ready for outreach
  • Time saved: ~40 hours of manual data entry

Technical Notes

  • Rate Limiting: Brave API free tier = 2,000 searches/month
  • Duplicates: Handled at workflow start, not during processing
  • Empty Results: Stores email + name even when enrichment fails
  • Model: Uses GPT-5 Nano for cost-effective parsing
  • Gmail Scope: Reads sent emails only (not inbox)

Cost Estimate

For processing 1,000 contacts:

  • Gmail API: Free
  • GPT-5 Nano: ~$0.50-2 (depending on email length)
  • Brave Search: Free (within 2K/month limit)
  • Google Sheets: Free
  • Total: Under $2 for 1,000 enriched contacts

Template Author:

Questions or need help with setup?
📧 Email:[email protected]
💼 LinkedIn:https://www.linkedin.com/in/vaclavcikl/