Process Invoice PDFs from Gmail to Sheets with Drive

Turn invoice PDFs in Gmail into structured Google Sheets records—automatically

This n8n automation workflow automatically processes supplier invoice PDFs received via Gmail: it extracts key invoice data, validates critical fields, detects duplicates, saves the PDF into the correct Google Drive folder, and logs results in Google Sheets—so you reduce manual data entry and prevent double processing.

What this workflow does

• Receives new invoices in Gmail: when a new email arrives, the workflow looks for PDF attachments and sends them for processing.
• Reads the invoice PDF: it extracts the text from the PDF and checks whether the document is readable enough for automatic processing.
• Collects important invoice data: it pulls key fields such as invoice number, company details, dates, amounts, VAT, and currency.
• Validates correctness: it checks for missing information and validates important items (including tax numbers, bank details, and consistency of invoice amounts).
• Detects duplicate invoices: it compares the extracted invoice data against records already stored in Google Sheets to reduce the risk of registering the same invoice twice.
• Routes next actions: correct invoices are marked as ready for payment, while suspicious, incomplete, or duplicate invoices are sent for manual review.
• Saves PDFs in Google Drive: the workflow stores each invoice PDF in the appropriate Google Drive location for organized retrieval.
• Logs invoice data to Google Sheets: results and extracted fields are recorded for tracking and downstream workflow use.

Use cases

• Accounts payable teams that want to automate invoice intake from supplier emails.
• SaaS operators who maintain invoice records in Google Sheets and need reliable duplicate prevention.
• Automation engineers building an invoice processing workflow that flags errors early for human review.

Technical details

• Gmail trigger to start when a new invoice email arrives.
• Google Drive to store invoice PDFs in organized folders.
• Google Sheets to log extracted invoice data and support duplicate checks.
• IF and Code steps to validate fields, assess readability, and route outcomes.
• Error trigger to handle failures during automated processing.