AI Invoice Processing Automation — n8n + Gmail + Google Sheets

The Problem Businesses receive dozens of invoices every week via email. Manually opening each PDF, reading the data, and entering it into spreadsheets wastes 2–4 hours daily — and introduces costly human errors. The Solution This AI-powered n8n automation workflow eliminates manual invoice processing completely. It runs 24/7 in the background and handles everything automatically — no human intervention required. How It Works Gmail is monitored for emails with PDF invoice attachments PDF text is extracted automatically using n8n's built-in file processor Groq AI (LLaMA 3.3) reads the invoice and extracts key fields Extracted data is appended to Google Sheets instantly What the AI Extracts Vendor name Invoice number Invoice date and due date Total amount and currency Full line items breakdown Key Results Data entry time reduced from 45 minutes to zero Works with any invoice format or layout 99%+ extraction accuracy using LLM Free to run — uses Groq free tier (1500 requests/day) Tech Stack Built using n8n (self-hosted), Groq AI API, Gmail OAuth2, and Google Sheets API. No paid AI subscription required. Use Cases Freelancers managing client invoices Accounting teams processing vendor bills E-commerce businesses handling supplier invoices Any business receiving PDF invoices via email