{"product_id":"gmail-openai-ap-invoice-forecast-n8n-to-google-sheets","title":"Gmail + OpenAI AP Invoice Forecast n8n to Google Sheets","description":"\u003ch3\u003eTurn invoice emails into automated cash-flow forecasts—syncing to Google Sheets with OpenAI\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow monitors your \u003cstrong\u003eGmail\u003c\/strong\u003e for unread invoice emails with PDF attachments, extracts invoice details using \u003cstrong\u003eOpenAI\u003c\/strong\u003e, logs everything in \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e, calculates upcoming cash needs, and sends you Gmail alerts—including a weekly accounts-payable digest.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDetects incoming invoices:\u003c\/strong\u003e Triggers when an unread Gmail message arrives and includes a PDF attachment, then downloads the invoice file.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExtracts invoice data with OpenAI:\u003c\/strong\u003e Reads the PDF text and uses \u003cstrong\u003eOpenAI (GPT-5-mini)\u003c\/strong\u003e to extract structured invoice fields, categorize the expense, and generate a one-sentence summary.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormalizes and prioritizes:\u003c\/strong\u003e Structures the extracted data, assigns \u003cstrong\u003eHigh\u003c\/strong\u003e or \u003cstrong\u003eNormal\u003c\/strong\u003e priority based on the invoice total, and records sender and receipt timestamp.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLogs to Google Sheets:\u003c\/strong\u003e Appends each invoice record to Google Sheets, then calculates \u003cstrong\u003emonth-to-date spend\u003c\/strong\u003e and \u003cstrong\u003eamounts due in the next 30 days\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSends Gmail notifications:\u003c\/strong\u003e Emails cash-flow metrics after each processed invoice, and sends a separate approval-style alert when priority is \u003cstrong\u003eHigh\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDelivers weekly AP overview:\u003c\/strong\u003e Every \u003cstrong\u003eMonday at 9am\u003c\/strong\u003e, reads the full invoice log from Google Sheets, builds an \u003cstrong\u003eHTML weekly digest\u003c\/strong\u003e (totals, category breakdown, and invoices due in 7 days), and emails it via Gmail.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eAccounts payable teams who want invoice parsing and tracking without manual spreadsheet updates.\u003c\/li\u003e\n  \u003cli\u003eSaaS operators forecasting cash by automatically estimating due amounts from emailed invoices.\u003c\/li\u003e\n  \u003cli\u003eAutomation engineers setting up an invoice-to-forecast pipeline in n8n using Gmail + OpenAI + Google Sheets.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrations \/ nodes:\u003c\/strong\u003e Gmail Trigger, Gmail, OpenAI (Chat Model, default \u003cstrong\u003egpt-5-mini\u003c\/strong\u003e), Google Sheets, plus workflow nodes such as \u003cstrong\u003eif\u003c\/strong\u003e, \u003cstrong\u003eset\u003c\/strong\u003e, \u003cstrong\u003ecode\u003c\/strong\u003e, and \u003cstrong\u003esticky note\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAuth required:\u003c\/strong\u003e Gmail OAuth2 for both the trigger and outgoing email actions; OpenAI API credential for invoice extraction; Google Sheets OAuth2 for logging and forecasting.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":45985520615603,"sku":"N8N-19392","price":16.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/jK6nEcvNExFq_Wksjz7Wk_82Z6qo0u.png?v=1788945321","url":"https:\/\/buyflowscripts.com\/products\/gmail-openai-ap-invoice-forecast-n8n-to-google-sheets","provider":"N8N Commerce","version":"1.0","type":"link"}