Extract and validate invoice PDFs into Excel with OpenAI GPT-4o-mini

by Tirumalesh Bodavula · 3 views · created 2026-09-22 · Invoice Processing, AI Summarization

What this workflow does

This AI workflow has 40 nodes and runs on a schedule (every day at 04:00). Along the way it connects OpenAI.

How it runs

Trigger: On a schedule (every day at 04:00).

1. Identify Deployment Mode (Code): runs custom JavaScript code
2. Check Local Deployment Status (If): checks a condition and branches into true / false
3. Verify Invoices Directory (Code): runs custom JavaScript code
4. Confirm Invoices Directory Exists (If): checks a condition and branches into true / false
5. Configure Local Drive Settings (Code): runs custom JavaScript code
6. Compile Final Configuration (Code): runs custom JavaScript code
7. Set Initial Configurations (Edit Fields (Set)): sets or maps fields
8. Retrieve Execution Info (Code): runs custom JavaScript code
9. Initialize Exec Report Content (Code): runs custom JavaScript code
10. Route by Input Source (Switch): routes items into 2 branches

…plus 29 more steps. See the full node list below.

Services it uses

OpenAI

Before you upgrade to n8n 3.0

Nodes used (11)

• Coden8n-nodes-base.code
• OpenAI@n8n/n8n-nodes-langchain.openAi
• Extract from Filen8n-nodes-base.extractFromFile
• Schedule Triggern8n-nodes-base.scheduleTrigger
• Read/Write Files from Diskn8n-nodes-base.readWriteFile
• Loop Over Items (Split in Batches)n8n-nodes-base.splitInBatches
• Convert to Filen8n-nodes-base.convertToFile
• Edit Fields (Set)n8n-nodes-base.set
• Ifn8n-nodes-base.if
• Mergen8n-nodes-base.merge
• Switchn8n-nodes-base.switch

From the author

Quick overview This workflow runs on a daily schedule, reads invoice PDFs from a local folder, extracts structured invoice data with OpenAI (gpt-4o-mini), validates required fields and subtotal math, and writes per-invoice Excel outputs plus an execution…

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