AI-Powered Email Auto-Responder with FAQ Knowledge Base - n8n Workflow

Small businesses and e-commerce operations needing 24/7 instant customer support.
Teams looking to automate initial customer service triage and response using AI.
Technical users seeking advanced n8n templates that combine LLMs with data sources (RAG).
Anyone interested in creating a robust and intelligent email processing n8n workflow.

Customer support can quickly become overwhelming. This powerful n8n workflow solves the bottleneck of routine inquiries by providing immediate, professional, and contextual responses. This automation starts with an n8n trigger listening to Gmail. It intelligently filters spam and newsletters, ensuring that the expensive AI processing is only used for genuine customer questions. By linking an OpenAI-powered AI Agent to a Google Sheets FAQ database, the system uses your own verified information (acting as a knowledge base) to generate accurate replies. This specific n8n workflow ensures high-quality support while dramatically reducing manual effort. Every interaction is logged to Google Sheets, providing a valuable audit trail and insight into common customer questions, making this n8n template highly practical for scaling support.

This automation is triggered instantly whenever a new email lands in the connected inbox, using the specific n8n trigger configured.

1. Incoming Email Detection: The Watch Gmail for New Incoming Emails n8n trigger starts the process upon receiving a message.


2. Inquiry Classification: The email content is passed to the Inquiry Filter (a LangChain Text Classifier) connected to an OpenAI model. This critical step determines if the email is a genuine 'Inquiry' or 'Not Inquiry' (spam, auto-reply, newsletter). Only emails classified as inquiries proceed.


3. Contextual Reply Generation: The core of the automation is the Reply Generator AI Agent n8n node. This agent is configured with a detailed prompt instructing it to act as a professional email assistant.


4. Knowledge Retrieval (RAG): The AI Agent leverages the Google Sheets Context Retrieval Tool. This tool searches a designated FAQ Google Sheet for information relevant to the user's questions, ensuring replies are based solely on pre-approved data.


5. Output Formatting: The agent’s response is forced into a structured JSON format via the Structured Output Parser n8n node, guaranteeing a clean, predictable reply text.


6. Sending the Response: The Send Reply to User n8n node sends the fully generated, professional response back to the original sender.


7. Logging and Audit: Finally, the Log Inquiries + Response to Google Sheet n8n node records the timestamp, original message, sender details, and the full AI response into a separate Google Sheet for historical tracking and analysis of this effective n8n workflow.

To deploy this comprehensive n8n workflow, follow these setup steps:

1. Import the JSON: Copy the provided n8n workflow JSON and paste it into your n8n instance using the 'Import from JSON' function.


2. Configure Credentials: This n8n template requires three main credentials:

1. Activate: Ensure all nodes are configured with the correct sheet IDs and credential connections. Set the Watch Gmail for New Incoming Emails n8n trigger to active and save the n8n workflow.

Watch Gmail for New Incoming Emails (n8n trigger): The starting point of this n8n workflow. It polls the inbox every minute for new messages.
Function: Initiates the automation upon receipt of a new email.
OpenAI Chat Model (GPT-4o Mini): Used as the underlying LLM for the Inquiry Filter to classify the intent of the incoming message.
Key Configuration: Uses gpt-4o-mini for efficient, fast classification.
Inquiry Filter (Text Classifier): Determines if the message is a support inquiry or irrelevant traffic.
Function: Filters out spam, newsletters, or auto-replies, saving processing costs.
Reply Generator AI Agent (LangChain Agent n8n node): The primary logic handler.
Function: Reads the inquiry, uses the Google Sheet tool to gather context, and composes a professional, factual response based on the structured instructions.
Google Sheets Context Retrieval Tool (n8n node): Acts as the RAG knowledge source for the AI Agent.
Function: Provides context from the FAQContext sheet based on the user's query.
Structured Output Parser (n8n node): Ensures the AI Agent's output adheres to a strict JSON schema.
Key Configuration: Defines the expected output key "respond".
Send Reply to User (Gmail n8n node): Executes the final action of the n8n workflow.
Function: Sends the AI-generated email reply back to the sender, dynamically using expressions to target the recipient address.
Log Inquiries + Response to Google Sheet (n8n node): Ensures accountability and data tracking.
Function: Appends the interaction details (timestamp, original text, AI reply) to the EnquiryLog sheet.