Screen supplier invoices for duplicates and PO mismatches with Gmail, Sheets and OpenAI
Ready for 3.0Ready for 3.0. This template uses no nodes that n8n 3.0 removes. No removed nodes, versions or helpers found. Static check, last run 2026-10-19.
What this workflow does
This AI workflow has 34 nodes and runs on Gmail events (plus 2 other triggers). Along the way it connects Gmail, Google Sheets and OpenAI Chat Model.
How it runs
Trigger: On Gmail events (plus 2 other triggers).
- Set Workflow Parameters (Edit Fields (Set)): sets 11 fields: sheet_id, ap_manager_email, finance_email…
- Read Ledger Data from Sheets (Google Sheets): uses Google Sheets
- Alert on Workflow Failure (Gmail): uses Gmail
- Read Supplier Master from Sheets (Google Sheets): uses Google Sheets
- Identify Open Invoices (Code): runs custom JavaScript code
- Aggregate: combines items into one
- Check for Reportable Items (If): checks a condition and branches into true / false
- Read Purchase Orders from Sheets (Google Sheets): uses Google Sheets
- Email Morning Report (Gmail): uses Gmail
- Aggregate: combines items into one
…plus 19 more steps. See the full node list below.
Services it uses
Before you upgrade to n8n 3.0
Nothing in this workflow is removed in n8n 3.0, so it should import and run after the upgrade.
- Still check Gmail Trigger below v1.4 runs as v1.4 (drafts skipped, max emails per poll) (When Invoice Email Arrives).
Nodes used (15)
- Gmail Trigger
n8n-nodes-base.gmailTrigger - Edit Fields (Set)
n8n-nodes-base.set - Google Sheets
n8n-nodes-base.googleSheets - Aggregate
n8n-nodes-base.aggregate - Code
n8n-nodes-base.code - Loop Over Items (Split in Batches)
n8n-nodes-base.splitInBatches - Extract from File
n8n-nodes-base.extractFromFile - Information Extractor
@n8n/n8n-nodes-langchain.informationExtractor - OpenAI Chat Model
@n8n/n8n-nodes-langchain.lmChatOpenAi - Switch
n8n-nodes-base.switch - Gmail
n8n-nodes-base.gmail - If
n8n-nodes-base.if - Schedule Trigger
n8n-nodes-base.scheduleTrigger - No Operation, do nothing
n8n-nodes-base.noOp - Error Trigger
n8n-nodes-base.errorTrigger
From the author
Quick overview This workflow monitors a Gmail inbox for PDF invoices, extracts key fields with OpenAI, and cross-checks them against Google Sheets supplier, purchase order, and ledger registers to detect duplicates, bank-detail changes, and PO/receiving…