Reply to contact form leads via Gmail and Google Sheets using OpenAI GPT-4o mini

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Built by TakatoYamada TakatoYamada
Created on June 05, 2026

Description

Quick overview
This workflow triggers on n8n form submissions, uses OpenAI (GPT-4o mini) to draft a short acknowledgment email, sends the auto-reply through Gmail, and appends the submission details to a Google Sheets spreadsheet.

How it works
Triggers when someone submits the n8n “Contact Us” form with their name, email, and message.
Sends the submission text to OpenAI (GPT-4o mini) to generate a warm auto-reply that promises a human follow-up within one business day.
Sends the generated reply to the submitter via Gmail with the subject “Thanks for reaching out!”.
Appends the form submission data to a Google Sheets worksheet for tracking.

Setup
Connect an OpenAI credential for the Chat model used to generate the email reply.
Connect a Gmail account credential and confirm the workflow is allowed to send email from that mailbox.
Connect a Google Sheets credential, replace the spreadsheet URL/ID in the Google Sheets step, and ensure the target sheet tab is named “Leads” (or update it to match your sheet).

Nodes Used (4)

Basic LLM Chain
@n8n/n8n-nodes-langchain.chainLlm
Gmail
n8n-nodes-base.gmail
Google Sheets
n8n-nodes-base.googleSheets
OpenAI Chat Model
@n8n/n8n-nodes-langchain.lmChatOpenAi