Extract Invoice Data from PDFs with AI - Google Sheets Email Alerts

Built by Setidure Technologies This smart n8n automation extracts invoice details from PDF files uploaded to Google Drive using AI, logs them to a Google Sheet, and notifies the billing team via email - all without manual intervention. Note: This workflow requires a self-hosted n8n instance with LangChain, LLM, and Google integrations configured. **What This Workflow Does** - Monitors a Google Drive folder for new invoice uploads - Extracts text and parses key invoice details using LLM via LangChain - Logs extracted data into a Google Sheet (Invoice Database) - Generates a summary email using GPT-4O-MINI (Greenie) - Sends the email to the billing team via Gmail **Prerequisites** - A Google Drive folder to monitor for PDF uploads - A Google Sheet named Invoice Database with the following columns: - Invoice Number, Client Name, Client Email, Client Address, Client Phone, Invoice Date, Due Date, Total Amount - Service account or OAuth credentials for: - Google Drive - Google Sheets - Gmail - LangChain + Ollama integration for LLM responses **Step-by-Step Setup Instructions** 1. Clone this workflow into your self-hosted n8n instance 2. Set up credentials: - Google Drive (for folder trigger) - Google Sheets (for data logging) - Gmail (for sending email) - Ollama (local LLM) or any connected LangChain provider 3. Configure the trigger node to watch your specific Invoice Uploads folder 4. Update the Google Sheet node with your Invoice Database sheet URL and column mapping 5. Test with a sample invoice to validate the AI extraction and email generation **Workflow Steps** ## Step 1: Trigger on New File in Google Drive Node Name: Watch for New Invoices Type: Google Drive Trigger Event: fileCreated Triggers when a new PDF file is uploaded to a designated folder ## Step 2: Download the Uploaded File Node Name: Download Invoice PDF Type: Download Binary Downloads the invoice file from Google Drive ## Step 3: Extract Raw Text from PDF Node Name: Extract PDF Text Type: Extract from File Extracts unstructured text content from the downloaded PDF ## Step 4: Parse Invoice Fields Using AI Node Name: Parse Invoice Data with LLM Type: LangChain Agent LLM is prompted to extract: - Invoice Number - Client Name, Email, Address, Phone - Invoice Date, Due Date, Total Amount Fields not found are skipped ## Step 5: Log Extracted Data to Google Sheet Node Name: Log to Invoice Database Type: Google Sheets Appends a new row with the extracted fields to the Invoice Database spreadsheet ## Step 6: Create Email Notification via LLM Node Name: Generate Billing Email Summary Type: LangChain Agent (GPT-4O-MINI) Prompt instructs AI to: - Act as "Greenie" from Green Grass Corp - Inform billing that a new invoice was processed - Confirm logging into the Invoice Database ## Step 7: Send the Email to Billing Team Node Name: Email Billing Team Type: Gmail Send To: billing@example.com Subject and body injected from LLM output ## Step 8: End Workflow Gracefully Node Name: End Type: No Operation Used to cleanly terminate the flow ## Example Output (Email) Subject: New Invoice Logged - Client: ABC Corp Hi Billing Team, A new invoice has been received and processed automatically. The following details have been extracted and logged into the Invoice Database: - Invoice Number: INV-1024 - Client: ABC Corp - Amount: $1,450 - Due Date: July 15, 2025 Please review the [Invoice Database](https://docs.google.com/spreadsheets/d/14FtgVUjy0tw4EQOB28wuCYOe6CELtt3Ujn-GsuDWY/edit?gid=0#gid=0) for full details. Regards, Greenie Green Grass Corp