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:
```json
{
"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**
1. **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
2. **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!
