Process scanned invoices with Google Drive, OCR & OpenAI to Google Sheets
### This template allows you to automatically process scanned invoices from Google Drive, extract key information using AI, and organize the data in Google Sheets with email notifications.
### Overview
This comprehensive workflow automates the entire invoice processing pipeline by monitoring a Google Drive folder for new invoice uploads, intelligently processing both PDF and image formats, extracting structured data using AI-powered information extraction, and automatically organizing the results in a Google Sheet while sending email notifications. The system handles various file formats and includes smart fallback mechanisms for challenging documents like CamScanner PDFs.
### How it Works
1. **File Monitoring**: The workflow continuously monitors a specified Google Drive folder for new invoice files using a trigger that checks every minute for newly created files.
2. **File Processing**: When new files are detected, the system downloads them and determines the file type (PDF or image) using a smart switch mechanism.
3. **Text Extraction**:
- For PDFs: Attempts direct text extraction first
- For Images: Uses OCR.Space API for optical character recognition
- For problematic PDFs (like CamScanner): Falls back to OCR processing
4. **AI Information Extraction**: Processes the extracted text through OpenAI's language model to identify and extract key invoice information including:
- Company name
- Total amount
- Currency
- Invoice date
- Invoice number
5. **Data Storage**: Automatically appends the extracted information to a Google Sheet with links back to the original scanned documents.
6. **Notification**: Sends formatted email notifications via Mailgun when new invoices are processed, including an HTML table summary.
### How to Use
1. **Setup Google Drive**: Create a dedicated folder in Google Drive for invoice uploads and note the folder ID.
2. **Configure Credentials**: Set up the following credential connections in n8n:
- Google Drive OAuth2 API
- Google Sheets OAuth2 API
- OpenAI API
- OCR.Space API
- Mailgun API
3. **Update Configuration**:
- Replace the Google Drive folder ID with your target folder
- Replace the Google Sheets document ID with your destination spreadsheet
- Update email addresses in the Mailgun node
4. **Test the Workflow**: Use the manual trigger to process existing invoices in your folder for initial testing.
5. **Activate**: Enable the workflow to start automatic monitoring of new invoice uploads.
## Requirements
**External APIs:**
- **OpenAI API** - For AI-powered information extraction from invoice text
- **OCR.Space API** - For optical character recognition of image-based invoices
- **Mailgun API** - For sending email notifications
**Google Services:**
- **Google Drive API** - For monitoring folders and downloading files
- **Google Sheets API** - For storing extracted invoice data
**Setup Prerequisites:**
- Google Drive folder dedicated to invoice uploads
- Google Sheet with appropriate column headers (date, company name, total, currency, invoice number, scan link, etc.)
- Email domain configured with Mailgun (or alternative email service)
- OCR.Space account for image processing capabilities: https://ocr.space/OCRAPI
**Recommended Settings:**
- Set the Google Drive trigger to check for new files every minute
- Ensure sufficient API rate limits for your expected invoice volume
- Configure proper error handling for failed OCR or AI extraction attempts
