Gmail PDF Invoice Extractor to Google Sheets + Telegram Alerts (n8n)

Turn Gmail invoice PDFs into clean Google Sheets rows—automatically, with Telegram alerts

This n8n workflow scans your Gmail for unread emails with PDF invoice attachments, extracts key invoice fields from the PDF text, checks for duplicates in Google Sheets, and uses Telegram to flag issues like duplicates or unreadable invoices.

What this workflow does

• Runs hourly and searches Gmail for unread emails containing PDF attachments, then downloads the attachment.
• Extracts invoice data from the PDF by parsing the PDF text to identify supplier, invoice number, dates, totals, VAT details, and currency—handling both UK and EU number formats.
• Detects incomplete invoices: if required fields can’t be read, it sends a Telegram message listing what couldn’t be extracted and stops without writing to Google Sheets.
• Prevents duplicates: reads existing rows from the Invoices sheet in Google Sheets and compares against the parsed invoice using supplier + invoice number + total as the matching key.
• Handles duplicates safely: if a duplicate is found, it sends a Telegram alert explaining which invoice was blocked and does not append a new row.
• Appends valid invoices: when the invoice is complete and non-duplicate, it formats a single clean record and adds it to the Invoices sheet in Google Sheets.

Use cases

• Accounts teams who receive monthly vendor invoices via email and want structured invoice tracking in Google Sheets.
• SaaS operators consolidating vendor spend data while getting real-time Telegram alerts for duplicates or parsing failures.
• Automation engineers needing a practical Gmail → PDF parsing → Google Sheets pipeline with safeguards.

Technical details

• n8n nodes/stack used: Gmail Trigger, if, set, code, telegram, and a sticky note for workflow context.
• Integrations: Gmail (unread PDF invoice detection), Google Sheets (Invoices sheet lookup + append), Telegram (alerts for missing fields and duplicates).
• Setup requirements: connect Gmail, update the Google Sheets URL to your spreadsheet with an Invoices sheet, and connect Telegram credentials.