Receipt extraction setup: receipt photos to Google Sheets rows with an n8n agent

What you need

• n8n and the OpenAI credential from the n8n AI agent lesson, or an OpenAI API key with some credit on it.
• A Google account with Drive and Sheets. A sheet called Invoices with headers Date, Category, Vendor and Amount.
• A clear photo: flat, well lit and in focus.

Build it

1. Create workflow, Add first step, On chat message. n8n's chat lets you attach files.
2. Click +, search agent, add AI Agent.
3. Chat Model: OpenAI Chat Model, credential OpenAI account, model gpt-4o so it can read images.
4. Memory: Simple Memory. It remembers the last 5 messages of each chat session.
5. Tool: Google Sheets Tool. Create new credential, leave Managed OAuth2, Sign in with Google.
6. Change Operation to Append Row, pick Invoices and Sheet1, and click ✦ next to each column.

The system message

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.

Open AI Agent, Add Option, System Message. It never says which value goes where: the column names do that.

Test and check

• Click Open chat, type Heres a receipt., attach the photo with the paperclip and send.
• Compare the new row with the receipt. In the lesson: Corner Mart, 31.57, filed as Groceries without being told.
• AI can misread a blurry photo. Check the rows before you use totals for taxes.