PaperPilot Uses Gemma to Turn Messy GST Invoices into Clean Records

PaperPilot is an invoice and expense assistant built for freelancers, consultants, and small agencies that struggle with folders of PDF invoices at tax time. The app uses Gemma, Google's open-weight model accessed through the Gemini API, to extract vendor details, dates, GST amounts, and totals from digital PDFs. Its validation layer checks the AI's output, flagging mismatched totals, invalid GSTINs, and unequal CGST and SGST values for human review. Duplicate detection, overdue flags, and bank statement matching are handled with ordinary code rather than AI, and personal identifiers are redacted before any text is sent to the model. Because Gemma's weights are public, the same model could later be self-hosted by users who need full control over their data.