{"product_id":"n8n-ai-invoice-approval-workflow-gpt-4o-mini-gmail-telegram","title":"n8n AI Invoice Approval Workflow: GPT-4o Mini + Gmail + Telegram","description":"\u003ch3\u003eAuto-approve vendor invoices with AI—then notify everyone in Gmail and Telegram\u003c\/h3\u003e\n\u003cp\u003eThis n8n AI Invoice Approval Workflow receives invoices via a webhook, uses \u003cstrong\u003eOpenAI (GPT-4o Mini)\u003c\/strong\u003e with your policy data from \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e to decide whether an invoice can be auto-approved or needs human review, logs every decision, and sends outcome notifications through \u003cstrong\u003eGmail\u003c\/strong\u003e and \u003cstrong\u003eTelegram\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReceives invoice submissions\u003c\/strong\u003e via a \u003cem\u003ePOST webhook\u003c\/em\u003e request.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormalizes and validates\u003c\/strong\u003e required fields—specifically checks that \u003cstrong\u003evendor email, invoice number, and amount\u003c\/strong\u003e are present.\u003c\/li\u003e\n  \u003cli\u003eIf required fields are missing, it sends:\n    \u003cul\u003e\n      \u003cli\u003ea \u003cstrong\u003eTelegram alert\u003c\/strong\u003e (intake error), and\u003c\/li\u003e\n      \u003cli\u003ean \u003cstrong\u003eemail notice via Gmail\u003c\/strong\u003e to alert finance.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003eIf valid, the workflow uses \u003cstrong\u003eOpenAI (GPT-4o Mini)\u003c\/strong\u003e and consults \u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e tables (VendorMaster and ApprovalPolicy) to produce:\n    \u003cul\u003e\n      \u003cli\u003ean approval decision (auto-approve vs human review),\u003c\/li\u003e\n      \u003cli\u003esuggested approver,\u003c\/li\u003e\n      \u003cli\u003ereason, and\u003c\/li\u003e\n      \u003cli\u003econfidence.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplies deterministic rules\u003c\/strong\u003e to force human review when the \u003cstrong\u003eamount is over 500,000\u003c\/strong\u003e or when the vendor is \u003cstrong\u003enot in the known-vendor list\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCalculates due dates and approval deadlines\u003c\/strong\u003e, then appends the invoice record and decision details to the \u003cstrong\u003eInvoices\u003c\/strong\u003e tab in Google Sheets.\u003c\/li\u003e\n  \u003cli\u003eSends notifications via \u003cstrong\u003eGmail\u003c\/strong\u003e and \u003cstrong\u003eTelegram\u003c\/strong\u003e:\n    \u003cul\u003e\n      \u003cli\u003econfirmation for auto-approved invoices to vendor and finance, or\u003c\/li\u003e\n      \u003cli\u003ereview request to the suggested approver and alerts to finance for manual review.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eFinance teams that want \u003cstrong\u003efaster invoice processing\u003c\/strong\u003e by automatically approving low-risk invoices.\u003c\/li\u003e\n  \u003cli\u003eOperations workflows that need \u003cstrong\u003epolicy-driven approvals\u003c\/strong\u003e using vendor and approval rules stored in Google Sheets.\u003c\/li\u003e\n  \u003cli\u003eSaaS operators who want \u003cstrong\u003eauditable logging\u003c\/strong\u003e of every invoice, decision, and reason.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWebhook\u003c\/strong\u003e for invoice intake\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eif\u003c\/strong\u003e, \u003cstrong\u003eset\u003c\/strong\u003e, and \u003cstrong\u003ecode\u003c\/strong\u003e nodes for validation, parsing, and rules\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOpenAI (GPT-4o Mini)\u003c\/strong\u003e to generate approval decision, reason, and confidence\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGoogle Sheets\u003c\/strong\u003e integration for VendorMaster, ApprovalPolicy, and Invoices logging\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGmail\u003c\/strong\u003e for email notifications\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTelegram\u003c\/strong\u003e for instant alerts and intake-error messages\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":45950240850099,"sku":"N8N-19128","price":71.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/N3SzzJmF8EyYZmtieImJl_9Uxg4Q3w.png?v=1788514138","url":"https:\/\/buyflowscripts.com\/products\/n8n-ai-invoice-approval-workflow-gpt-4o-mini-gmail-telegram","provider":"N8N Commerce","version":"1.0","type":"link"}