Multi-Attachment Invoice Sorter and Sequential Batch OCR

How it works

1. 1.Trigger the workflow manually via Manual Trigger to produce a realistic 4-attachment email payload.
2. 2.Deconstruct the attachments array into individual items and validate file extensions and size limits.
3. 3.Route valid files to OCR simulation and invalid files to rejection formatting using an If node.
4. 4.Extract simulated accounting fields (invoice number, amount, currency, confidence) and classify document types.
5. 5.Normalize rejected items with explicit rejection causes and zeroed balances in a Set node.
6. 6.Append both processing streams and compile a consolidated financial audit ledger item.

Use cases

• Accounts payable teams receiving vendor emails with combined invoices, agreements, and receipts.
• Preventing batch OCR crashes caused by non-supported file formats or oversized files.
• Generating structured pre-audit accounting summaries for internal financial review.

Requirements

• n8n instance supporting Code v2, Set v3.4, and Merge v3.2 nodes.
• No external credentials required for the self-contained demonstration flow.
• For production: connect Gmail/IMAP trigger, live Document AI / OCR HTTP service, and Google Drive / Sheets nodes.

Setup and testing in n8n

1. Click 'Test step' on Manual Trigger to emit the fictional email payload with 4 mixed attachments.
2. Inspect Explode & Validate Attachments to ensure 4 distinct items are emitted with format flags.
3. Verify that 3 items traverse the valid OCR path while the .exe file is directed to the rejection branch.
4. Inspect Build Financial Audit Ledger to confirm a single consolidated output object with complete summary counts and ledger rows.

Service Value

Ready-made workflow template for automation delivery and service execution.