Automate Email Validation with n8n & Google Sheets Trigger

Opening Problem Statement

Meet Sarah, a marketing manager responsible for sending monthly newsletters to thousands of subscribers stored in a Google Sheets document. Each campaign’s success depends heavily on email deliverability. Yet Sarah spends hours manually verifying the accuracy and validity of email addresses, battling duplicate entries and invalid contacts, which leads to bounced emails, wasted marketing budget, and inaccurate campaign metrics.

On average, Sarah spends over 5 hours every week cross-checking thousands of emails, handling duplicates, and trying to update the validity status manually. This tedious process is error-prone and drains her productivity, causing delayed campaigns and loss in customer engagement.

What This Automation Does

This n8n workflow automates Sarah’s email validation process directly tied with her Google Sheets mailing list. Every time her sheet data changes, this workflow springs into action. Here’s exactly what happens:

• Triggers automatically every minute checking for updates or new entries in a Google Sheets spreadsheet.
• Detects and removes any duplicate emails to ensure uniqueness in her list.
• Sends each email to an external email validation API (Effibotics) to check if the email is deliverable.
• Immediately updates the status back into the Google Sheet, marking emails with validation results.
• Ensures that invalid or problematic email addresses are clearly flagged to prevent sending campaigns to them.
• Eliminates manual error and saves hours of tedious data cleanup every week.

Thanks to this precise integration, Sarah’s email campaign deliverability improves significantly, while she saves at least 5 hours weekly on email verification tasks.

Prerequisites ⚙️

• Google Sheets account with your mailing list prepared.
• Access to n8n automation platform (cloud or self-hosted).
• Google Sheets Trigger node set up with OAuth2 credentials.
• Google Sheets node with proper permissions for updating.
• HTTP Request node access to an email validation API (e.g., Effibotics) and API key.

Optional: For self-hosting n8n, consider reliable hosts like Hostinger for seamless operation.

Step-by-Step Guide 🔌

Step 1: Connect your Google Sheets Trigger Node

In the n8n editor, add a Google Sheets Trigger node. This node listens for changes in your Google Sheets document.

• Click the + icon → Search “Google Sheets Trigger” → Add to canvas.
• Under Document ID, paste your Google Sheets URL or select from the dropdown.
• Choose the appropriate sheet (usually Sheet1 or by gid=0).
• Configure the trigger to poll every minute for changes under pollTimes.
• Select your Google OAuth2 credentials tied to your Google account.

After configuration, this node monitors your spreadsheet continuously and activates the workflow upon changes.

Common mistake: Forgetting to select the correct sheet or incorrect OAuth credentials leading to no trigger.

Step 2: Add the Remove Duplicates Node

Add a Remove Duplicates node next. It ensures only unique emails proceed.

• Click + → Search “Remove Duplicates” → Add.
• Set Compare to Selected Fields and enter Email in the Fields to Compare.

This weed out duplicate entries to avoid redundant validation calls and maintain a clean list.

Common mistake: Missing or misspelling the “Email” field causing duplicates to slip through.

Step 3: Filter by Existing Email Status Using an IF Node

Add an If node to ensure only emails without a validation status get processed.

• Add an If Email Exists node.
• Under Conditions, select the field Status and set the condition to check if it is empty.

This step prevents unnecessary re-validation, saving API calls and workflow time.

Common mistake: Not matching the exact field name or case causing unwanted filtering behavior.

Step 4: Send Emails for Validation via HTTP Request

Add an HTTP Request node configured to call the external email validation API.

• Choose POST method.
• URL is set to https://email.effibotics.com/api.
• Set Content Type to application/x-www-form-urlencoded.
• Body Parameters include the email field: email={{ $json.Email }}.
• Headers include your API key (e.g., api_key: 9Q6H0QETRF=GS1).
• Retry on failure enabled to ensure robustness.

This node fetches deliverability status for each email.

Common mistake: Using the wrong content type or missing the API key which causes errors.

Step 5: Update Google Sheets with Validation Result

Add a Google Sheets node to update each row with validation results.

• Set operation to Update.
• Choose the spreadsheet and sheet as in the first step.
• Use auto-map input data mode and set Email as the matching column.
• This updates existing rows with the new validation data.

Outcome: Your Google Sheets list now shows which emails are valid or not after each workflow run.

Common mistake: Incorrect match column(s) causing values to update wrong rows.

Customizations ✏️

• Change validation API: In the HTTP Request node, update the URL and headerParameters to connect to a different email validation service.
• Adjust polling time: Increase or decrease the polling frequency in Google Sheets Trigger to control how often emails are checked.
• Add additional fields: Expand the Remove Duplicates fields or Google Sheets update columns to include name or status details.

Troubleshooting 🔧

Problem: “Empty Status blocks email processing”

Cause: The If node condition might not exactly match the Status field or case sensitivity issues.

Solution: Recheck the exact field name in your sheet and confirm case sensitivity is correct in the condition.

Problem: “HTTP Request fails with 401 Unauthorized”

Cause: API key in HTTP Request node header is invalid or expired.

Solution: Update API key in HTTP Request node credentials and verify with provider.

Pre-Production Checklist ✅

• Ensure Google OAuth credentials have read/write access to your sheet.
• Test Google Sheets Trigger fires on actual data changes (edit some sheet entries).
• Verify unique emails pass through Remove Duplicates node.
• Confirm the HTTP Request node successfully returns validation responses.
• Check Google Sheets updates reflect correctly after workflow execution.

Deployment Guide

Once configured, activate the workflow toggle in n8n. It will automatically run every minute, watching your spreadsheet.

Monitor execution and logs in n8n dashboard regularly to catch any failures or API issues. This ensures your email list stays fresh, validated, and ready to use for your campaigns.

Conclusion

By following this guide, you transformed Sarah’s manual, error-prone email verification process into an automated, reliable system using n8n and Google Sheets. This workflow saves at least 5 hours weekly, reduces bounce rates, and improves marketing efficiency by keeping email lists accurate.

Next steps? Consider automating follow-ups for invalid emails, integrating with campaign tools like Mailchimp or ActiveCampaign, or expanding validation to phone numbers or other contacts.

With this workflow, you have the power to simplify and improve your email marketing operations significantly.