# AI invoice agent with OpenAI and Gmail: n8n workflow template

> Started by an event in a connected app, and works across Gmail and Google Sheets. It hands the judgement calls to OpenAI.

Source: https://millionrounds.com/workflow/ai-invoice-agent-with-openai-and-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)

# AI invoice agent with OpenAI and Gmail

Started by an event in a connected app, and works across Gmail and Google Sheets. It hands the judgement calls to OpenAI. 11 steps, 1 loop or waits: a working afternoon to understand properly.

Medium Calls a model: OpenAI

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

**11 steps** Medium: a working afternoon

**0** Branches: places the flow splits

**1** Loop or waits

**2** Services it connects to

## The flow

Starts it 1 Model 3 Logic 3 Service 4

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

- 1 **When clicking ‘Execute workflow’** Manual trigger *Starts it*
- 2 **GPT - 4.1 mini** Lm Chat Open Ai *Model*
- 3 **Google Sheets** Google Sheets *Service*
- 4 **AI Agent** Agent *Model*
- 5 **Information Extractor** Information Extractor *Model*
- 6 **Filter** Filter *Logic*
- 7 **CraftMyPDF** Craft My Pdf *Service*
- 8 **Edit Fields** Set *Logic*
- 9 **Gmail** Gmail *Service*
- 10 **Loop Over Items** Split In Batches *Logic*
- 11 **Google Sheets1** Google Sheets *Service*

## How it's built

- **Starts on:** An event in a connected app
- **Steps:** 11, 1 loop or waits
- **Size:** Medium: a working afternoon
- **Connects to:** Gmail, Google Sheets
- **Model:** OpenAI

## Questions

What does it need to run?

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

What starts it?

It starts on an event in a connected app.

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. 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%2Fai-invoice-agent-with-openai-and-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)

## Workflows like it

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

- [**AI-powered invoice analysis & anomaly detection with OpenAI** 11 steps · calls a model · Airtable, Gmail](https://millionrounds.com/workflow/ai-powered-invoice-analysis-and-anomaly-detection-with-opena)
- [**Analyze invoices and predict cash flow with Gemini** 11 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/analyze-invoices-and-predict-cash-flow-with-gemini)
- [**Automate WhatsApp invoice processing with OCR and OpenAI** 11 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/automate-whatsapp-invoice-processing-with-ocr-and-openai)
- [**Automate invoice processing from Gmail with Azure GPT-4.1** 11 steps · calls a model · Gmail](https://millionrounds.com/workflow/automate-invoice-processing-from-gmail-with-azure-gpt-4-1)
- [**Automated invoice parsing with LlamaCloud and Claude** 11 steps · calls a model · Google Drive, Google Sheets](https://millionrounds.com/workflow/automated-invoice-parsing-with-llamacloud-and-claude)
- [**Automated invoice workflow with Google Workspace** 11 steps · calls a model · Gmail, Google Docs](https://millionrounds.com/workflow/automated-invoice-workflow-with-google-workspace)