Document AI

n8n Invoice Extraction with Validation and Review

An n8n invoice workflow extracts headers and line items, translates descriptions, checks totals, and sends reviewable data to Google Sheets for an Excel handoff.

N8n invoice workflow from intake through extraction, translation and checks into human review and spreadsheet output.

Illustrative n8n invoice workflow from intake through extraction, translation and checks into human review and spreadsheet output.

Earlier invoice orchestrator canvas, showing intake, extraction and spreadsheet handoffs. The 97.9% annotation is an internal target, not a verified project accuracy result.Earlier extraction canvas with model processing and Greek-to-English translation. The benchmark and ranking annotations do not establish this project's measured performance.Historical PDF-splitting workflow. Combined multi-invoice PDF processing was an extension in progress, outside the delivered core described here.Project folder scanner used by the invoice intake workflow to find files in its folder structure.Project error-notification workflow, showing the log, failed-file handling and email notification path.

The problem

Invoice processing involved more than copying totals. The workflow needed to retain original descriptions, add English translations, and fit an existing spreadsheet review process without overwriting formula columns.

The task was to connect PDF and image intake to structured invoice data, while making questionable documents, duplicate records and extraction failures visible to a reviewer.

What I built

Google Drive intake and n8n orchestration for individual PDF and image invoices.
AI extraction of invoice headers and line items, retaining Greek descriptions alongside English translations.
Document classification, VAT and total checks, with success, review, duplicate and failed states. Duplicate candidates remain available for human acceptance or rejection.
Correction memory from records marked Active or Corrected. It can reuse supplier details and line descriptions while preserving raw audit values and formula columns.
Google Sheets output designed for the existing Excel and Power Query handoff, plus failure logging and notifications.

The outcome

The delivered core connects intake, extraction, checks and reviewable spreadsheet output. Review states and retained source values give finance staff a way to investigate an invoice before accepting it. The combined multi-invoice PDF extension remained work in progress.

Who this approach suits

Finance and operations teams that need invoice extraction to fit their spreadsheet rules and approval process. To scope similar work, bring redacted invoices, required fields, document languages and the workbook structure.

Discuss an invoice automation workflow.

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