# Approve invoices with Claude and Google Drive: n8n workflow

> Started by an event in a connected app, and works across Google Drive and Google Sheets. 28 steps, 3 branches, 1 loop or waits: large, and worth reading...

Source: https://millionrounds.com/workflow/approve-invoices-with-claude-and-google-drive (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)

# Approve invoices with Claude and Google Drive

Started by an event in a connected app, and works across Google Drive and Google Sheets. 28 steps, 3 branches, 1 loop or waits: large, and worth reading before you trust it with anything live.

Large

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fapprove-invoices-with-claude-and-google-drive)

**28 steps** Large: read it before trusting it with anything live

**3** Branches: places the flow splits

**1** Loop or waits

**2** Services it connects to

## The flow

Starts it 2 Logic 17 Service 9

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

- 1 **When File Added to Drive Inbox** Google Drive trigger *Starts it*
- 2 **Manual Execution Trigger** Manual trigger *Starts it*
- 3 **Download Invoice from Drive** Google Drive *Service*
- 4 **Set Configuration Parameters** Set *Logic*
- 5 **Extract Base64 from Binary** Code *Logic*
- 6 **Normalize Invoice Data** Code *Logic*
- 7 **Prepare Vision API Request** Code *Logic*
- 8 **Post to Anthropic Vision API** Http Request *Service*
- 9 **Parse Vision API Response** Code *Logic*
- 10 **Perform Arithmetic Check** Code *Logic*
- 11 **Read Sheets for Duplicates** Google Sheets *Service*
- 12 **Check for Invoice Duplicates** Code *Logic*
- 13 **If Immediate Review Needed** If *Logic*
- 14 **Build Approval Request** Code *Logic*
- 15 **If Under Approval Threshold** If *Logic*
- 16 **Post Approval Request Notification** Http Request *Service*
- 17 **Automatically Approve Invoice** Code *Logic*
- 18 **Wait for Approval Action** Wait *Logic*
- 19 **Aggregate for Logging** Code *Logic*
- 20 **Process Approval Decision** Code *Logic*
- 21 **Read Vendor Total from Sheets** Google Sheets *Service*
- 22 **Calculate Vendor Total** Code *Logic*
- 23 **Construct Ledger Entry** Code *Logic*
- 24 **Append Ledger in Sheets** Google Sheets *Service*
- 25 **If Invoice Approved** If *Logic*
- 26 **Move Approved to Processed** Google Drive *Service*
- 27 **Move Denied to Flagged** Google Drive *Service*
- 28 **Send Final Notification** Http Request *Service*

## How it's built

- **Starts on:** An event in a connected app
- **Steps:** 28, with 3 branches, 1 loop or waits
- **Size:** Large: read it before trusting it with anything live
- **Connects to:** Google Drive, Google Sheets
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account, plus your own Google Drive and Google Sheets accounts. 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?

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?

Take your time. At 28 steps it is large: read it before trusting it with anything live.

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 28 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%2Fapprove-invoices-with-claude-and-google-drive)
- **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.

[Google Drive](https://millionrounds.com/workflows?service=Google+Drive#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.

- [**Kick off client projects after Stripe payment** 28 steps · ClickUp, Gmail](https://millionrounds.com/workflow/kick-off-client-projects-after-stripe-payment)
- [**Automate income and expense tracking in Google Sheets** 27 steps · Google Sheets, Telegram](https://millionrounds.com/workflow/automate-income-and-expense-tracking-in-google-sheets)
- [**Deliver digital products with WhatsApp and Telegram** 27 steps · Google Sheets, Telegram](https://millionrounds.com/workflow/deliver-digital-products-with-whatsapp-and-telegram)
- [**Automated invoice processing with Telegram and OpenAI** 27 steps · calls a model · Google Sheets, Telegram](https://millionrounds.com/workflow/automated-invoice-processing-with-telegram-and-openai)
- [**Manage restaurant orders, upsells, and payments with Telegram** 29 steps · calls a model · Google Sheets, Slack](https://millionrounds.com/workflow/manage-restaurant-orders-upsells-and-payments-with-telegram)
- [**Process and approve invoices with OpenAI and Google Sheets** 27 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/process-and-approve-invoices-with-openai-and-google-sheets)