# Process Gmail invoices with OpenAI and Google Sheets: n8n workflow

> Started by a clock, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI.

Source: https://millionrounds.com/workflow/process-gmail-invoices-with-openai-and-google-sheets (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 Gmail invoices with OpenAI and Google Sheets

Started by a clock, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI. 18 steps, 2 branches: a working afternoon to understand properly.

Medium Calls a model: OpenAI

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

**18 steps** Medium: a working afternoon

**2** Branches: places the flow splits

**0** Loops or waits

**3** Services it connects to

## The flow

Starts it 2 Model 1 Logic 6 Service 9

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

- 1 **Monitor Incoming Invoice Emails** Gmail trigger *Starts it*
- 2 **Daily Invoice Reminder Scheduler** Schedule trigger *Starts it*
- 3 **Download Invoice Attachment** Gmail *Service*
- 4 **Load Pending Invoice Records** Google Sheets *Service*
- 5 **Extract Text from Invoice PDF** Extract From File *Service*
- 6 **Calculate Remaining Due Days** Code *Logic*
- 7 **AI Invoice Data Extraction** Open Ai *Model*
- 8 **Generate Reminder Priority & Status** Code *Logic*
- 9 **Format Extracted Invoice Data** Code *Logic*
- 10 **Check Reminder Action Required** If *Logic*
- 11 **Check Existing Invoice Record** Google Sheets *Service*
- 12 **Send Invoice Reminder Email** Gmail *Service*
- 13 **Send Slack Reminder Notification** Slack *Service*
- 14 **Is Duplicate Invoice?** If *Logic*
- 15 **Update Invoice Status in Sheet** Google Sheets *Service*
- 16 **Prepare Duplicate Invoice Alert** Set *Logic*
- 17 **Save Invoice to Tracker Sheet** Google Sheets *Service*
- 18 **Send Duplicate Alert to Slack** Slack *Service*

## How it's built

- **Starts on:** A clock
- **Steps:** 18, with 2 branches
- **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 a clock.

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. 18 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 18 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-gmail-invoices-with-openai-and-google-sheets)
- **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.

- [**Approve employee expenses with OpenAI and Google Sheets** 18 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/approve-employee-expenses-with-openai-and-google-sheets)
- [**Audit expense reports with OpenAI and Slack** 18 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/audit-expense-reports-with-openai-and-slack)
- [**Automate invoice processing with OCR.Space and OpenAI** 18 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/automate-invoice-processing-with-ocr-space-and-openai)
- [**Automate invoice processing with OpenAI and XML** 18 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/automate-invoice-processing-with-openai-and-xml)
- [**Automated invoice processing system with Airtable** 18 steps · calls a model · Airtable, Gmail](https://millionrounds.com/workflow/automated-invoice-processing-system-with-airtable)
- [**Automated tax filing with OpenAI** 18 steps · calls a model · Gmail, Google Drive](https://millionrounds.com/workflow/automated-tax-filing-with-openai)