n8n Webhook: Filter Spam & Send Leads to Google Sheets + Gmail

Stop Spam. Capture Real Leads. Auto-Reply with Gmail (n8n Webhook → Google Sheets)

This n8n automation workflow accepts website form submissions via a webhook, filters out likely spam/bot enquiries, appends valid leads to Google Sheets, and sends an acknowledgement email to the submitter using Gmail—while logging rejected submissions for review.

What this workflow does

• Receives enquiries as a POST request sent to an n8n webhook.
• Normalizes fields (e.g., name, email, message, page, honeypot) into a consistent structure and stamps a received timestamp.
• Validates and flags junk by checking:
  • Email format
  • Honeypot usage
  • Disposable domain indicators
  • Short or link-heavy messages
  • Common cold-pitch patterns
• Routes results:
  • Valid enquiries go to the main lead flow.
  • Flagged submissions go to an exceptions flow with rejection reasons.
• Enriches lead context with fields like email domain, whether the address is personal, best-guess account name/website, an enquiry ID, and a default status.
• Updates Google Sheets:
  • Appends valid leads to the Leads tab
  • Appends rejected entries to the Exceptions tab for auditing (nothing is discarded)
• Sends acknowledgement email to the submitter via Gmail.

Use cases

• Convert “Contact Us” submissions into clean CRM-ready rows in Google Sheets—without spam noise.
• Send immediate confirmation emails for legitimate enquiries while keeping bot attempts in an Exceptions tab.
• SaaS operators validating inbound form traffic before sales review.

Technical details

• Webhook node to receive POST submissions
• if, set, and code logic for normalization, validation, and routing
• gmail node to send acknowledgement emails
• Sticky note elements for workflow documentation

Setup: Connect Google Sheets (ensure tabs named “Leads” and “Exceptions”), connect Gmail for the sending account, then copy the generated webhook URL into your website form.