# Process email invoices with OCR and OpenAI: n8n workflow

> Started by an arriving email, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI.

Source: https://millionrounds.com/workflow/process-email-invoices-with-ocr-and-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)

# Process email invoices with OCR and OpenAI

Started by an arriving email, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI. 20 steps, 2 branches, 1 loop or waits: a working afternoon to understand properly.

Medium Calls a model: OpenAI

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fprocess-email-invoices-with-ocr-and-openai)

**20 steps** Medium: a working afternoon

**2** Branches: places the flow splits

**1** Loop or waits

**3** Services it connects to

## The flow

Starts it 1 Model 4 Logic 9 Service 6

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

- 1 **Invoice Email Trigger** Gmail trigger *Starts it*
- 2 **OpenAI GPT-4** Lm Chat Open Ai *Model*
- 3 **OpenAI GPT-4 for Parser** Lm Chat Open Ai *Model*
- 4 **Workflow Configuration** Set *Logic*
- 5 **AI Invoice Extractor** Agent *Model*
- 6 **Invoice Schema Parser** Output Parser Structured *Model*
- 7 **Capture Invoice Metadata** Set *Logic*
- 8 **Validate and Recalculate Totals** Code *Logic*
- 9 **Check File Type** If *Logic*
- 10 **Mask PII Data** Code *Logic*
- 11 **Extract Text from PDF** Extract From File *Service*
- 12 **OCR for Images** Http Request *Service*
- 13 **Check if Review Needed** If *Logic*
- 14 **Merge OCR Results** Merge *Logic*
- 15 **Send Review Request** Slack *Service*
- 16 **Create QuickBooks Bill** Quickbooks *Service*
- 17 **Wait for Human Review** Wait *Logic*
- 18 **Prepare Audit Log Entry** Set *Logic*
- 19 **Log to Audit Trail** Google Sheets *Service*
- 20 **Send Success Notification** Slack *Service*

## How it's built

- **Starts on:** An arriving email
- **Steps:** 20, with 2 branches, 1 loop or waits
- **Size:** Medium: a working afternoon
- **Connects to:** Gmail, Google Sheets, Slack
- **Model:** OpenAI

## Questions

What does it need to run?

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

What starts it?

It starts on an arriving email.

Does it use AI?

Yes. It calls OpenAI. Model calls are billed by the provider, not by n8n.

How long does it take to set up?

Plan an afternoon. 20 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 20 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%2Fprocess-email-invoices-with-ocr-and-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)[Slack](https://millionrounds.com/workflows?service=Slack#library)

## Workflows like it

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

- [**Collect invoices from Gmail and save them** 20 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/collect-invoices-from-gmail-and-save-them)
- [**Extract and log invoice data to Google Sheets with Ainoflow** 20 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/extract-and-log-invoice-data-to-google-sheets-with-ainoflow)
- [**Extract invoice data from Google Drive to Sheets with Mistral** 20 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/extract-invoice-data-from-google-drive-to-sheets-with-mistra)
- [**Manage school fee receipts and GPT-4o reminders with Razorpay** 20 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/manage-school-fee-receipts-and-gpt-4o-reminders-with-razorpa)
- [**Multi-modal expense tracking with Telegram and Gemini** 20 steps · calls a model · Google Sheets, Telegram](https://millionrounds.com/workflow/multi-modal-expense-tracking-with-telegram-and-gemini)
- [**Vet supplier payments with Bright Data and OpenAI** 20 steps · calls a model · Slack, n8n data table](https://millionrounds.com/workflow/vet-supplier-payments-with-bright-data-and-openai)