{"product_id":"detect-duplicate-invoices-in-google-sheets-with-gemini-slack","title":"Detect Duplicate Invoices in Google Sheets with Gemini + Slack","description":"\u003ch3\u003eDetect Potential Duplicate Invoices in Google Sheets—Then Alert Slack and Place an ERP Hold (with Gemini)\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow automatically checks newly added invoices in Google Sheets for duplicates using exact and fuzzy matching, classifies the result with \u003cstrong\u003eGoogle Gemini\u003c\/strong\u003e, and then either alerts \u003cstrong\u003eSlack\u003c\/strong\u003e and calls an \u003cstrong\u003eERP payment-hold API\u003c\/strong\u003e or logs a safe approval back to Sheets.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTriggers\u003c\/strong\u003e when a new invoice row is added to the \u003cstrong\u003e“New_Invoices”\u003c\/strong\u003e sheet in Google Sheets.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLoads invoice data\u003c\/strong\u003e from both \u003cstrong\u003e“New_Invoices”\u003c\/strong\u003e and \u003cstrong\u003e“Invoice_History”\u003c\/strong\u003e, then builds two comparison lists.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompares invoices\u003c\/strong\u003e using exact + fuzzy matching on \u003cstrong\u003einvoice number\u003c\/strong\u003e, \u003cstrong\u003esupplier name\u003c\/strong\u003e, \u003cstrong\u003eamount\u003c\/strong\u003e, and \u003cstrong\u003einvoice date\u003c\/strong\u003e to produce a duplicate flag, risk score, and best match details.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCalls Google Gemini\u003c\/strong\u003e to classify each invoice as \u003cstrong\u003eExact Duplicate\u003c\/strong\u003e, \u003cstrong\u003eNear Duplicate\u003c\/strong\u003e, or \u003cstrong\u003eLegitimate Invoice\u003c\/strong\u003e, including confidence, reasoning, and a recommended action.\u003c\/li\u003e\n  \u003cli\u003eIf Gemini flags \u003cstrong\u003eExact Duplicate\u003c\/strong\u003e or \u003cstrong\u003eNear Duplicate\u003c\/strong\u003e:\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003ePosts a detailed alert to Slack\u003c\/strong\u003e (duplicate details and recommended action).\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eSends a POST request\u003c\/strong\u003e to an \u003cstrong\u003eERP payment-hold endpoint\u003c\/strong\u003e to stop payment processing.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003eIf Gemini classifies it as \u003cstrong\u003elegitimate\u003c\/strong\u003e:\n    \u003cul\u003e\n      \u003cli\u003e\n\u003cstrong\u003eAppends an approval record\u003c\/strong\u003e to the \u003cstrong\u003e“Safe Invoices”\u003c\/strong\u003e sheet.\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLogs outcomes\u003c\/strong\u003e to the \u003cstrong\u003e“Fraud Cases”\u003c\/strong\u003e sheet in Google Sheets (in all cases) for auditability.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eCatch duplicate supplier invoices before they reach AP\/ERP payment.\u003c\/li\u003e\n  \u003cli\u003eDetect “near duplicates” caused by re-submissions, minor typos, or formatting differences.\u003c\/li\u003e\n  \u003cli\u003eCentralize investigation history with \u003cstrong\u003eFraud Cases\u003c\/strong\u003e and \u003cstrong\u003eSafe Invoices\u003c\/strong\u003e logging.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrations:\u003c\/strong\u003e Google Sheets, Slack, Google Gemini, and an ERP payment-hold API (POST endpoint).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes\/logic:\u003c\/strong\u003e \u003ccode\u003eif\u003c\/code\u003e, \u003ccode\u003eset\u003c\/code\u003e, \u003ccode\u003ecode\u003c\/code\u003e, \u003ccode\u003emerge\u003c\/code\u003e, \u003ccode\u003eslack\u003c\/code\u003e, \u003ccode\u003eaggregate\u003c\/code\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRequires:\u003c\/strong\u003e Google Sheets OAuth with access to sheets\/tabs: \u003cstrong\u003e“New_Invoices”\u003c\/strong\u003e, \u003cstrong\u003e“Invoice_History”\u003c\/strong\u003e, \u003cstrong\u003e“Safe Invoices”\u003c\/strong\u003e, and \u003cstrong\u003e“Fraud Cases”\u003c\/strong\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":45872783851699,"sku":"N8N-18494","price":26.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/f9Lqc7GOLn9CBeP-3ZiZO_c92PboSQ.png?v=1787216516","url":"https:\/\/buyflowscripts.com\/products\/detect-duplicate-invoices-in-google-sheets-with-gemini-slack","provider":"N8N Commerce","version":"1.0","type":"link"}