# Automate invoice processing & stock management with Gmail: 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/automate-invoice-processing-and-stock-management-with-gmail (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)

# Automate invoice processing & stock management with Gmail

Started by an arriving email, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI. 12 steps, 1 branch: a working afternoon to understand properly.

Medium Calls a model: OpenAI

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fautomate-invoice-processing-and-stock-management-with-gmail)

**12 steps** Medium: a working afternoon

**1** Branch: places the flow splits

**0** Loops or waits

**3** Services it connects to

## The flow

Starts it 1 Model 3 Logic 1 Service 7

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

- 1 **Gmail Trigger** Gmail trigger *Starts it*
- 2 **Structured Output Parser** Output Parser Structured *Model*
- 3 **OpenAI Chat Model** Lm Chat Open Ai *Model*
- 4 **Extract from File** Extract From File *Service*
- 5 **Extract Invoice Record** Agent *Model*
- 6 **Sales Order Creation** Google Sheets *Service*
- 7 **Stock & Shortage Check** Google Sheets *Service*
- 8 **If Negative** If *Logic*
- 9 **Create Purchase Requisition** Google Sheets *Service*
- 10 **Create Work Order** Google Sheets *Service*
- 11 **Send a message** Gmail *Service*
- 12 **Send Order Summary** Slack *Service*

## How it's built

- **Starts on:** An arriving email
- **Steps:** 12, with 1 branch
- **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. 12 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 12 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%2Fautomate-invoice-processing-and-stock-management-with-gmail)
- **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.

- [**AI auto-save Gmail receipts to Google Sheets + Google Drive** 12 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/ai-auto-save-gmail-receipts-to-google-sheets-google-drive)
- [**AI business proposal generator with Gemini and Google Drive** 12 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/ai-business-proposal-generator-with-gemini-and-google-drive)
- [**Automate employee trip expense processing with Jotform** 12 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/automate-employee-trip-expense-processing-with-jotform)
- [**Automated Invoice Flow Manager with OpenAI and Gmail** 12 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/automated-invoice-flow-manager-with-openai-and-gmail)
- [**Automated trip expense claim form with OpenAI and Google Drive** 12 steps · calls a model · Email, Google Drive](https://millionrounds.com/workflow/automated-trip-expense-claim-form-with-openai-and-google-dri)
- [**Capture, classify, and log Gmail PDF invoices with Gemini** 12 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/capture-classify-and-log-gmail-pdf-invoices-with-gemini)