Automating Invoice Entry into Xero with n8n and OpenAI

I recently helped a small retail business automate their daily vendor invoice process, which was previously done entirely by hand. The accounts team had to manually open each invoice email, read the PDF, and type all the details into Xero. It was time-consuming and prone to mistakes.

The business receives multiple invoices every day, usually sent as PDF attachments to a shared email inbox. Their process looked like this:

• Open each email and check for a PDF invoice
• Read the invoice carefully and extract fields like vendor name, invoice number, date, due date, and total amount
• Manually enter all of that into Xero
• Repeat this for every email, every day

This manual approach was slowing the team down and often led to delays or incorrect entries.

Solution

I built a complete automation using n8n, OpenAI, and Xero to handle the full invoice workflow — from email to Xero.

Here’s how the automated system works:

Email Monitoring:

• Checks the Outlook inbox for new emails in the invoice folder
• Automatically downloads the PDF if it exists (if not, it skips the email)

Data Extraction:

• Uses OpenAI to read and extract key fields from the PDF invoice:vendor name, address, invoice number, currency, invoice date, due date, amount, and more
• Connects to Xero to get the correct account code from the chart of accounts

Vendor Matching:

• Checks if the vendor already exists in Xero
• If not, it creates a new contact automatically

Invoice Creation:

• Creates the invoice in Xero using the extracted details
• Adds the correct line items, due dates, and amounts

Notification:

• Sends a Slack message to confirm the invoice was successfully created

How It Handles Different Invoices

The best part is that this system works even if the invoice layout or design is different. Using OpenAI, the workflow extracts fields from various PDF formats without needing different templates or rules for each one.

Result

The business now has a hands-free invoice process.

Invoices from email are automatically processed and created in Xero — no more manual data entry, no more opening emails one by one, and no more copying and pasting into forms.

This has saved the team hours of repetitive work each week and eliminated errors caused by manual entry.

Final Thoughts

This project shows how small businesses can use automation and AI together to take care of repetitive tasks. If you’re spending too much time handling invoices manually, there’s a smarter way to do it.

If you’d like to explore how automation could work for your business, I’d be happy to chat.