Automated Invoice Processing and Approval Workflow

This n8n workflow automates the entire process of invoice handling, from collection to approval and data entry. It is designed to streamline invoice management for businesses by integrating Google Drive, Gmail, Google Sheets, and OpenAI’s GPT-4. The process begins with monitoring a designated Google Drive folder, incoming Gmail attachments, and a web-based upload form for new invoices. When a PDF invoice is detected, the workflow downloads and extracts raw text from the file. Using OpenAI’s GPT-4, the text is parsed into structured invoice data, including key details like invoice number, vendor, date, total amount, and itemized expenses; it also categorizes the invoice.

Following data extraction, the system sends an approval request email to a reviewer, providing options to approve or reject the invoice along with optional notes. If approved, the invoice data is automatically recorded into a Google Sheet for bookkeeping. If rejected, an alert email is sent to the finance team for further action. The workflow includes decision logic to handle approval or rejection, ensuring human oversight while maintaining automation efficiency. This setup is ideal for organizations seeking to reduce manual data entry, improve accuracy, and expedite their invoice approval cycle.