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

Description

🧾 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!