Gmail Finance Email Classification with OpenAI → Google Sheets (n8n)

Automatically classify Gmail finance emails and log them to Google Sheets—powered by OpenAI

This n8n workflow monitors your Gmail inbox hourly, uses OpenAI to classify finance-related emails, extracts key details, stores any supporting PDFs in Google Drive, and records everything in Google Sheets. It also labels and marks processed emails as read, while sending error alerts to Gmail and Discord when something goes wrong.

What this workflow does

• Runs every hour to fetch all unread Gmail messages.
• Classifies each email with OpenAI as sales, expense, settlement, transaction, notification, or other based on the subject and body.
• Expense handling: OpenAI extracts invoice fields, the workflow downloads any PDF attachment from Gmail, uploads it to Google Drive, appends an expense row to Google Sheets (including the Drive link), then labels the email and marks it as read.
• Sales handling: OpenAI extracts order details, the workflow generates a PDF with PDFBolt, uploads it to Google Drive, appends a sales row to Google Sheets with the Drive link, labels the email, and marks it as read.
• Settlement handling: OpenAI extracts payout details, downloads any PDF attachment, uploads it to Google Drive, appends a settlement row to Google Sheets with the Drive link, then labels and marks the email as read.
• Other categories: For transaction, notification, and other emails, it applies the corresponding Gmail label and marks the message as read.
• Error handling: If any step fails, an n8n Error Trigger sends the error to OpenAI for a plain-language summary and posts an alert (including the summary) to Discord and via Gmail.

Use cases

• Bookkeeping workflows that turn unread Gmail receipts/invoices into structured Google Sheets entries.
• Sales order tracking from emailed confirmations into a spreadsheet with archived PDFs.
• Automated payout/settlement logging with Drive-linked evidence for audits.

Technical details

• Integrations/nodes: Gmail, OpenAI, Google Sheets, Google Drive, Discord, PDFBolt, and workflow control nodes like if, switch, split out, and code.