Auto-Respond to Gmail Inquiries using OpenAI, Google Sheet & AI Agent

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Built by Billy Christi Billy Christi
Created on June 13, 2026

Description

Who is this for?

This workflow is ideal for:

Customer support teams looking to reduce manual response time
SaaS companies that frequently receive product inquiries
E-commerce stores with common customer questions about orders, shipping, and returns

What problem is this workflow solving?

Manually responding to repetitive customer emails is inefficient, prone to inconsistency, and time-consuming. This workflow solves the issue by:

Automatically replying to real customer inquiries 24/7
Ensuring every response is consistent, friendly, and based on approved knowledge
Preventing responses to non-inquiries like newsletters or confirmations
Logging every interaction for traceability, analysis, and compliance

What this workflow does

This AI-powered Gmail auto-responder intelligently handles inbound emails with the following steps:

Monitors your Gmail inbox for new incoming emails in real time
Classifies each email as either an “Inquiry” or “Not Inquiry” using GPT-4
Gets context from a Google Sheets FAQ database
The context will be used to determine the most accurate and helpful response
Generates a professional reply only if it’s a valid inquiry (e.g., pricing, refund, product details)
Builds a context-aware, helpful response using verified knowledge only
Sends the reply to the original sender automatically
Logs everything to a Google Sheet — original email, AI response, timestamp, and email address

Example Use Case:

An email comes in:
"Hi, I want to know your pricing and refund policy."

The workflow:

Detects it’s an inquiry
Finds the pricing and refund FAQs in your Google Sheet
Sends back a professional response like:
"Hi! Thanks for reaching out. Our pricing starts at \$99/month. Refunds can be requested within 30 days of purchase. Let us know if you have more questions!"
Logs the interaction to your “Enquiry\_Log” tab

Setup

Copy the Google Sheet template here:
👉 Gmail Auto-Responder – Google Sheet Template
This contains:

A FAQ_Context tab (your knowledge base)
An Enquiry_Log tab (interaction logs)

Connect your Gmail account to the Gmail Trigger and Gmail Send nodes

Add your OpenAI API key in the classification and response generator nodes

Link the Google Sheet in both the FAQ lookup and logging nodes

Test with a sample email — try asking a pricing and refund question to see the complete process in action

How to customize this workflow to your needs

Adjust tone or brand voice** in the AI prompt for a more casual or formal reply
Modify classification rules** if your use case includes more custom logic
Expand the FAQ database** to include new questions and answers
Add multilingual support** by customizing the AI prompt to detect and respond in different languages
Integrate CRM or ticketing systems** (like HubSpot, Zendesk, or Notion) to log or escalate unanswered queries

Contact me for consulting and support:
📧 [email protected]

Nodes Used (6)

AI Agent
@n8n/n8n-nodes-langchain.agent
Gmail
n8n-nodes-base.gmail
Google Sheets
n8n-nodes-base.googleSheets
OpenAI Chat Model
@n8n/n8n-nodes-langchain.lmChatOpenAi
Structured Output Parser
@n8n/n8n-nodes-langchain.outputParserStructured
Text Classifier
@n8n/n8n-nodes-langchain.textClassifier