Automate Invoice Processing with AI Data Extraction, Google Drive & Sheets

🧾 Automated Invoice Processing - n8n Workflow

📖 Workflow Description

This n8n workflow automates the complete processing of PDF invoices with AI-powered data extraction. The workflow monitors a Google Drive folder, extracts important invoice data, and automatically organizes files in a structured filing system.

🎯 Features

🔍 Automatic monitoring** of a Google Drive folder for new PDF files 🤖 AI-powered data extraction** from invoices (customer, amount, date, etc.) 📁 Intelligent file sorting** by year and month 📝 Automatic renaming** following a consistent schema 📊 Central documentation** in Google Sheets

🔧 Required Integrations

Required Accounts: Google Drive (with folder permissions) Google Sheets (with write permissions) Google Gemini API (for AI data extraction)

Used n8n Nodes: Google Drive Trigger Google Drive (File Operations) Google Sheets Extract from File (PDF) Information Extractor (LangChain) Google Gemini Chat Model Split in Batches

📋 Workflow Steps in Detail

1. Monitoring & Triggering Google Drive Trigger** monitors a defined input folder Automatically starts when new PDF files are detected Split in Batches** enables batch processing of multiple files

2. File Processing GetFile** downloads PDF files from Google Drive ExtractFromPDF** converts PDF content to text Supports scanned documents as well

3. AI Data Extraction The Information Extractor node with Google Gemini extracts: Company name/sender Customer name and customer number Invoice number and date Net and gross amount Value-added tax Article description Month and year (for sorting)

4. Automatic Filing GetYearFolder** searches/creates year folders GetMonthFolder** searches/creates month folders MoveFile** moves invoice to correct folder UpdateFileName** renames file (schema: "Customer Month Year")

5. Documentation AddToOverview** enters all data into Google Sheets table Enables central overview and analysis

⚙️ Setup Instructions

Step 1: Prepare Google Drive

Create the following folder structure in Google Drive:

📁 [Input Folder] (e.g., "Invoices-Inbox") 📁 [Main Folder] (e.g., "Accounting") └── 📁 2024 ├── 📁 January ├── 📁 February ├── 📁 March └── ... (all months) └── 📁 2025 └── ... (all months)

Step 2: Create Google Sheets Table

Create a spreadsheet with the following columns: Customer Number Customer [Company Name] Location Invoice Date Invoice Number VAT Net Amount Month Year

Step 3: Configure Workflow

Configure Google Drive Trigger: Select your input folder as "Folder to Watch" Set "Event" to "fileCreated" Activate the trigger

Search files and folders: Select the same input folder as filter

Customize Information Extractor: Adapt attribute names to your needs Change company name in description Adjust system prompt if needed

GetYearFolder & GetMonthFolder: Set the correct folder ID for your main folder Check query string for year/month search

AddToOverview: Select your Google Sheets table Map columns according to your table

🔧 Customization Options

Extend Data Extraction: Add more attributes in the Information Extractor node: { "name": "Payment Terms", "description": "Days until payment due", "required": false }

Customize File Naming: Change the schema in the UpdateFileName node: "{{ $('Information Extractor').item.json.output.InvoiceNumber }} - {{ $('Information Extractor').item.json.output.Customer }}"

Change Monitoring Interval: In Google Drive Trigger under "Poll Times" select different intervals.

🚨 Important Notes

⚠️ Permissions: Google Drive: Full access to configured folders Google Sheets: Write permission for target table Google Gemini: Valid API key required

📝 Data Format: Works with German number formats (comma as decimal separator) Date format: YYYY-MM-DD Supports various PDF formats

🔄 Error Handling: Workflow fails if folders are missing Incomplete PDFs may lead to incomplete extractions Check logs for troubleshooting

📊 Performance & Limitations

Processing time:** 30-60 seconds per invoice Supported formats:** PDF (text and OCR) Batch processing:** Yes, multiple files simultaneously AI accuracy:** ~95% for standardized invoices

🧪 Testing

Run Test: Upload a test PDF to the input folder Monitor workflow execution in n8n Check results in Google Sheets Verify correct file movement and renaming

Error Diagnosis: For errors: check n8n logs Consider Google API quotas Validate folder permissions

📄 License & Support

This workflow can be used and customized freely. For configuration questions or issues, check the n8n community or Google API documentation.

Tip: Start with a few test invoices before using the workflow in production!