AI Receipt Extractor: Receipts to Google Sheets with n8n

Step 1: Create a workflow

In Module 2 your agent wrote ideas into a spreadsheet. This time it reads. You'll drop a photo of a receipt into a chat, and the agent pulls out the date, the store, the total, picks a category, and adds a row to a sheet. You already have n8n and an OpenAI key from Module 2, so we start right here on the Overview page.

Step 2: Add the first step

An empty canvas. Every workflow starts with a trigger, the thing that kicks it off.

Step 3: On chat message

We want to hand the agent a receipt by chatting with it, and n8n's chat lets you attach files. So pick on chat message.

Step 4: Close the node

The defaults are fine. The chat stays private to you while you build. Close it.

Step 5: Add the next step

Now, what happens when a message comes in.

Step 6: Search for the agent

There are hundreds of nodes, so search.

Step 7: AI Agent

AI Agent. This is the part that looks at the receipt and decides what to do with it.

Step 8: Close the node

See how the prompt already comes from the chat trigger? Whatever you type in the chat goes straight to the agent. We'll give it instructions at the end, once it has everything it needs. Close it for now.

Step 9: Give it a brain

That red warning means the agent has no brain.

Step 10: Search for OpenAI

Step 11: OpenAI Chat Model

OpenAI chat model.

Step 12: Pick your credential

Here's the payoff from Module 2. You don't need a new key.

Step 13: Reuse your OpenAI key

Pick OpenAI account. That's the key you saved in Module 2. n8n keeps it, so every workflow can reuse it. If you skipped Module 2, you'd choose create new credential and paste a key instead.

Step 14: Change the model

Now the model. The default is fine for text, but this agent has to read a picture.

Step 15: gpt-4o

Pick gpt-4o. It reads images reliably and quickly, and it's the model we used when we built this for real.

Step 16: Close the node

Brain's in. Close it.

Step 17: Add memory

Next, memory. It lets you say things like, actually, call that one office supplies, and the agent knows which receipt you mean.

Step 18: Simple Memory

Simple memory. It lives inside n8n, so there is nothing to sign up for.

Step 19: Close the node

It keys the memory to your chat session and remembers the last five messages. That's plenty. Close it.

Step 20: Add a tool

Now the part that makes it an agent and not just a chatbot: a tool. This is how it writes to your spreadsheet.

Step 21: Search for Sheets

Step 22: Google Sheets Tool

Google sheets tool.

Step 23: Open the credential list

It opens set to get rows, which reads a sheet. We'll change that. But first, n8n needs permission to touch your Google account.

Step 24: New credential

Create new credential.

Step 25: Sign in with Google

Leave it on managed OAuth. That's the easy way, n8n handles the setup.

Step 26: Pick your account

A Google window pops up. Pick the account that owns the Drive you want the spreadsheet in.

Step 27: Allow access

Google checks that you trust n8n dot cloud. You'll see connection successful, and the window closes on its own.

Step 28: Go to Google Drive

Connected. Now the tool needs a spreadsheet to write to, and we haven't made one. Leave this open and switch to the Google Drive tab.

Step 29: New

This is a bookkeeping folder, shared with an accountant. Keeping the sheet here means they see every receipt as it lands.

Step 30: Google Sheets

Google sheets.

Step 31: Blank spreadsheet

Blank spreadsheet.

Step 32: Create and share

Because the folder is shared, Google asks before making something new in it. That's what we want. If your folder isn't shared, you won't see this.

Step 33: Name it

A new tab opens. Name it first, so you can find it in n8n's list.

Step 34: Header: Date

Now the column headers. These matter. The agent fills the sheet column by column, so these names tell it what goes where. A1, Date.

Step 35: Header: Category

B1, Category.

Step 36: Header: Vendor

C1, Vendor.

Step 37: Header: Amount

And D1, Amount. Four columns. That is the whole spreadsheet.

Step 38: Back to n8n

Back to the n8n tab. The sheets tool is still open, right where you left it.

Step 39: Change the operation

First, fix the operation. Get rows reads from a sheet. We want to add to it.

Step 40: Append Row

Append row. Every receipt becomes a new row at the bottom. Notice the node on the canvas renames itself to match.

Step 41: Pick the document

Now which spreadsheet.

Step 42: Invoices

There's Invoices, the one you just made. n8n can see it because of the Google account you connected.

Step 43: Pick the tab

Now the tab inside it.

Step 44: Sheet1

Sheet one. n8n reads the header row and lists your four columns.

Step 45: Let the model fill Date

Here's the clever bit. Each column has a little sparkle button.

Step 46: Category

Category.

Step 47: Vendor

Vendor.

Step 48: Amount

And amount. All four now say defined automatically by the model.

Step 49: Close the node

The tool is wired to the sheet. Close it.

Step 50: Open the agent

Last piece. Right now the agent has a brain, a memory and a tool, but no idea what it's for. Double click the AI agent.

Step 51: Add an option

Step 52: System Message

System message. This is the standing instruction it reads before every chat.

Step 53: Write the instructions

It's three short lines. You'll get a receipt. Pull out the date, vendor and amount. Come up with a category yourself. Then use the sheets tool to add it. Notice we never say where each value goes. The column names in the sheet take care of that.

You are a helpful assistant. You will receive a receipt.

Extract the date, vendor, and amount. Come up with a category.

Use the google sheets tool to add the receipt to the sheet.

Step 54: Close the node

That's the whole workflow. Close it and let's try it.

Step 55: Open the chat

Step 56: Say hello

It doesn't need to be clever, the instructions already say what to do. Heres a receipt is enough.

Step 57: Attach the receipt

Now the receipt.

Step 58: Find it

Step 59: receipt.png

Pick receipt dot png. The photo, not the PDF.

Step 60: Open

It sits under the message, ready to go.

Step 61: Send it

Send. Watch the canvas. The trigger fires, the agent reads the picture with gpt-4o, and then calls the sheets tool. It takes a few seconds.

Step 62: Check the receipt

Everything turned green. Before you trust it, check its work. Corner Mart, April twenty fourth, total thirty one fifty seven.

Step 63: See the row

Now switch to the Invoices tab. There's the row. Date, groceries, Corner Mart, thirty one fifty seven. It matches the receipt, and it picked groceries without being told. Drop in another receipt and you get another row.