Email List Hygiene - Automated Weekly Validator Overview Validates email lists through automated checks, categorizes results as Valid/Invalid/Risky, updates Google Sheets in real-time, and delivers HTML reports. Runs every Friday at 5 PM via cron scheduling. Workflow Architecture Schedule Trigger → Read Google Sheets → Loop (Process Each Email) → Validate API → IF Branch (Valid/Invalid) → Update Google Sheets → Merge → Loop Back → Calculate Statistics → Send Email Report Loop Mechanism Split in Batches processes one email at a time Each email: validate → branch → update sheet → merge → continue Loop accumulates all results internally "Done" output triggers statistics calculation after all emails processed Health Score Formula Score = (Valid% × 100) - (Invalid% × 20) - (Risky% × 10) Bounded: 0-100 Ranges: 80-100: Excellent (green) 60-79: Good (orange) 0-59: Needs Attention (red) Prerequisites Required: Google account with Sheets access Email validation API (VerifiEmail) n8n v1.0+ Google Sheet Structure Column Type Filled By row_number Number Auto-generated name Text You email Text You status Text Workflow checked_at Text Workflow notes Text Workflow Only populate first three columns. Setup 1. Import Template Import JSON file to n8n via Workflows → Add workflow → Import from File 2. Configure Credentials Google Sheets OAuth2 (used by 3 nodes): Create credential via any Google Sheets node Grant spreadsheet permissions Apply same credential to all Google Sheets nodes Validation API: Get API key from https://verifi.email Add credential to "Validate Email Address" node Gmail OAuth2: Add credential to "Send Weekly Report" node Grant email sending permissions 3. Connect Google Sheet In all three Google Sheets nodes: Select your spreadsheet from Document dropdown Select sheet tab Verify "Column to Match On" = row_number (for Update nodes) 4. Set Email Recipient In "Send Weekly Report" node: Change "Send To" from placeholder to your email Optional: Add CC/BCC for multiple recipients 5. Test Add 3-5 test emails (mix of valid/invalid) Click "Execute Workflow" Verify sheet updates and email arrives 6. Activate Toggle "Active" switch. Workflow runs automatically every Friday at 5 PM. Customization Change Schedule: Edit "Weekly Schedule" node cron expression: Daily 9 AM: 0 9 * * * Monday 5 PM: 0 17 * * 1 First of month: 0 9 1 * * Email Design: Edit HTML in "Send Weekly Report" message field. Modify colors (search hex codes), text, or add branding. Archive Invalid Emails: Add Google Sheets Append node after "Update Invalid Status" → create "Invalid_Archive" tab → append email, name, reason, date Slack Notifications: Add Slack node after email report → configure channel → use summary text from statistics Rate Limiting: Add Wait node (1-2 seconds) after validation for large lists to prevent API throttling Troubleshooting "Column not found": Verify exact column names in sheet: row_number , name , email , status , checked_at , notes (case-sensitive) Only processes 1 email: Check Google Sheets node Range field is empty or set to include all rows. Verify "Use Header Row" enabled. Wrong statistics: Enable "Execute Once" in Calculate Statistics node settings (gear icon) Email not arriving: Check spam/promotions folder, verify Gmail credential authorized, confirm recipient address correct API errors: Verify API key valid, check quota not exceeded, test with simple email like [email protected] Merge node error: Confirm both Update nodes connect to Merge inputs (top and bottom). Check both branches execute successfully. Validation Checks Each email undergoes: RFC 5322 format compliance MX record existence (domain has mail servers) SMTP verification (mailbox exists) Disposable email service detection Catch-all domain detection Categories: Valid: All checks passed Invalid: Critical checks failed Risky: Disposable or catch-all domain Support Check execution logs in n8n Executions tab for errors. Use "Execute Node" on individual nodes to isolate issues. Visit n8n community forum for additional help. Tags email-validation marketing-automation data-cleaning google-sheets scheduled-workflow deliverability list-hygiene