OpenAI GPT-4o Bank Statement Expense Reports (n8n)

Upload a bank statement and instantly generate an interactive expense report with OpenAI—inside n8n

This n8n workflow takes your bank statement upload (CSV or text-based PDF), parses the transactions, uses OpenAI (gpt-4o-mini) to categorize merchants, and returns a polished HTML expense report with category totals, monthly summaries, recurring-charge detection, and a downloadable CSV.

What this workflow does

• Receives a file upload via an n8n Form trigger (production form URL from the “Upload Statement” trigger).
• Detects file type (PDF or CSV/text) and extracts the text accordingly.
• Parses and normalizes transactions—cleaning up dates, amounts, and descriptions into a structured transaction list.
• Deduplicates merchants and sends the unique merchant list to OpenAI to:
  • assign a spending category,
  • standardize the payee/merchant name.
• Computes financial insights including spend/income totals, category breakdowns, month-by-month summaries, largest transactions, and repeating charges with annualized cost.
• Generates narrative commentary via OpenAI, including short observations and questions to validate.
• Builds an interactive HTML report (charts/tables, recurring charges, full transaction table) and provides a CSV download in the form response.

Use cases

• Turn quarterly bank-export statements into categorized expense reports for SaaS operations.
• Audit spending trends by month and spot recurring charges you may want to renegotiate.
• Provide finance-ready summaries to stakeholders without manual spreadsheet cleanup.

Technical details

• OpenAI: Uses an OpenAI Chat Model node (gpt-4o-mini) connected to the workflow’s AI processing.
• n8n nodes / logic: if, code, form, merge, sticky note.
• Workflow output: interactive HTML expense report + downloadable CSV, returned as the form response.