# Extract and validate invoice PDFs with OpenAI: n8n workflow

> Started by someone submitting a form, and works across Gmail and Google Sheets. 11 steps: a working afternoon to understand properly.

Source: https://millionrounds.com/workflow/extract-and-validate-invoice-pdfs-with-openai (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Money admin](https://millionrounds.com/workflows?category=Money+admin#library)

# Extract and validate invoice PDFs with OpenAI

Started by someone submitting a form, and works across Gmail and Google Sheets. 11 steps: a working afternoon to understand properly.

Medium

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fextract-and-validate-invoice-pdfs-with-openai)

**11 steps** Medium: a working afternoon

**0** Branches: places the flow splits

**0** Loops or waits

**2** Services it connects to

## The flow

Starts it 1 Logic 5 Service 5

The steps in the order they run, from what starts it.

- 1 **1. Form, Upload Invoice PDF** Form trigger *Starts it*
- 2 **2. Extract From File, PDF to Text** Extract From File *Service*
- 3 **3. HTTP, AI Extract Invoice Fields** Http Request *Service*
- 4 **4. Code, Parse Invoice JSON Safely** Code *Logic*
- 5 **5a. Sheets, Log Invoice Header** Google Sheets *Service*
- 6 **5b. Split Out, Line Items** Split Out *Logic*
- 7 **6. Code, Add Unique Key and Line Metadata** Code *Logic*
- 8 **7. Sheets, Log Each Line Item** Google Sheets *Service*
- 9 **8. Aggregate, Collect All Line Items** Aggregate *Logic*
- 10 **9. Code, Verify Totals and Build Report** Code *Logic*
- 11 **10. Gmail, Send Extraction Report** Gmail *Service*

## How it's built

- **Starts on:** Someone submitting a form
- **Steps:** 11
- **Size:** Medium: a working afternoon
- **Connects to:** Gmail, Google Sheets
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account, plus your own Gmail and Google Sheets accounts. You connect your own accounts after importing it; none are included.

What starts it?

It starts on someone submitting a form.

Does it use AI?

No. Every step is fixed logic or a call to a service, so it does the same thing every time.

How long does it take to set up?

Plan an afternoon. 11 steps is enough that you should read each one before running it.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

**Before you run it**

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 11 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fextract-and-validate-invoice-pdfs-with-openai)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

## Connects to

Each opens the other workflows that use it.

[Gmail](https://millionrounds.com/workflows?service=Gmail#library)[Google Sheets](https://millionrounds.com/workflows?service=Google+Sheets#library)

## Workflows like it

Also money admin, with the same services where possible, closest in size first.

- [**Automate payment receipts: Email, archive, and track** 11 steps · Gmail, Google Drive](https://millionrounds.com/workflow/automate-payment-receipts-email-archive-and-track)
- [**Detect Stripe payment anomalies with Groq and Supabase** 11 steps · Google Sheets, Slack](https://millionrounds.com/workflow/detect-stripe-payment-anomalies-with-groq-and-supabase)
- [**Expense logging with Telegram and Google Sheets** 11 steps · Google Sheets, Telegram](https://millionrounds.com/workflow/expense-logging-with-telegram-and-google-sheets)
- [**Generate invoices, save to Drive and send email to customer** 11 steps · Email, Google Drive](https://millionrounds.com/workflow/generate-invoices-save-to-drive-and-send-email-to-customer)
- [**Handle failed Stripe payments with Slack and ClickUp** 11 steps · ClickUp, Gmail](https://millionrounds.com/workflow/handle-failed-stripe-payments-with-slack-and-clickup)
- [**Log LINE receipt photos to Google Sheets with OpenAI** 11 steps · Google Sheets](https://millionrounds.com/workflow/log-line-receipt-photos-to-google-sheets-with-openai)