n8n Webhook to Google Sheets Lead Capture + Slack Alerts

Capture website leads with an n8n Webhook, save them to Google Sheets, and alert your team in Slack—only for truly new contacts.

This n8n automation turns any POSTed lead submission into a clean, deduplicated record in Google Sheets and sends a Slack alert only when a genuinely new lead is captured. If the same email comes in again, your sheet gets updated quietly—no noisy notifications.

What this workflow does

• Receives lead submissions via Webhook (from a website form or any JSON sender).
• Normalizes and validates input by mapping common field-name variants into a consistent lead schema, flagging free-mail domains, and ensuring the submission contains a usable email address.
• Returns immediate feedback: valid leads receive a JSON acknowledgement; invalid submissions return HTTP 400 with an error message.
• Prevents duplicates in Google Sheets by looking up the submitted email in the Leads worksheet.
• If the email is new, appends a full lead record including first_seen, last_seen, times_seen, then posts a formatted “new lead” message to Slack.
• If the email already exists, updates the existing row by bumping times_seen and refreshing last_seen, without sending a Slack notification.

Use cases

• Collect SaaS demo requests or contact form submissions directly from your website into Google Sheets.
• Keep sales/ops informed in Slack when a truly new lead arrives—while ignoring repeat form submissions.
• Maintain accurate lead engagement metrics using first_seen / last_seen / times_seen for the same email.

Technical details

• n8n nodes/logic: webhook, if, code, slack, google sheets, sticky note.
• Google Sheets setup: create a spreadsheet with a worksheet named Leads and headers: email, name, company, phone, source, message, first_seen, last_seen, times_seen, status.
• Auth: Google Sheets OAuth2 credentials (with Google Sheets API and Google Drive API enabled).