Lead Webhook to Gmail Alerts & Acknowledgements (n8n)

Instant Gmail Alerts + Lead Acknowledgements from a Header-Authenticated Webhook (n8n)

This n8n workflow listens for new lead submissions on a header-authenticated webhook, verifies and normalizes the data, prevents duplicate notifications, and then sends two Gmail emails—an admin alert and a lead acknowledgement—before returning a JSON response to the caller.

What this workflow does

• Receives lead data via POST webhook: A header-authenticated webhook accepts lead details from your form or CRM.
• Validates and normalizes payload: Incoming fields are normalized (e.g., trimming the name and lowercasing the email). Invalid payloads are rejected with an HTTP 400 JSON response.
• Prevents duplicate processing: The workflow checks an n8n Data Table log for an existing row with the same leadId, ensuring notifications aren’t sent twice.
• Handles duplicates gracefully: If the lead was already processed, it returns a JSON response indicating the request is a duplicate.
• Sends Gmail emails for new leads: For new leads, it sends:
  • Admin notification email
  • Lead acknowledgement email
  Either email can fail without stopping the overall run.
• Logs outcomes and responds: Email send statuses and any errors are written back to the Data Table, and the caller receives a success JSON payload.

Use cases

• SaaS operators who need reliable lead capture notifications with instant Gmail alerts and automatic acknowledgements.
• Automation engineers integrating an existing CRM/form system with an authenticated webhook.
• Teams that must avoid duplicate outreach by enforcing idempotency using a Data Table log.

Technical details

• Webhook with Header Auth credential
• if and set nodes for validation and normalization
• data table workflow logging (recommended name: lead_notification_log with columns like leadId, executionId, adminEmailStatus, adminEmailError, leadEmailStatus, leadEmailError)
• Gmail OAuth2 integration for both email steps
• merge to consolidate processing results before replying