Bulk-parse inbound e-invoices from Gmail into a flat Google Sheet

Between Christmas and mid-January I was out for three weeks, and the supplier invoices for three of my clients had been stacking up in their inboxes — roughly a hundred and eighty attachments. I'm a freelance bookkeeper; I prep their data for DATEV. Opening each PDF, typing invoice numbers, net amounts and VAT rates into a spreadsheet isn't twelve hours for me, it's closer to two days. That backlog pushed me to build this.

The workflow runs on demand: it searches a Gmail mailbox for messages matching a query I give it (typically something like has:attachment newer_than:30d), pulls out the XML and PDF attachments, asks invoice-api.xhub to parse whatever is actually an e-invoice, flattens each parsed result into a wide row, and appends the rows to a Google Sheet I keep per client.

The Gmail query is the knob I turn most. The default is the last twenty matching messages — enough for a morning's backlog. For a quarter's worth I bump the cap, narrow the from: to a specific supplier, or scope to a Gmail label. The flow is a manual trigger by design: I run it, watch the rows land, then switch to the sheet.

What ends up in the sheet

Around 25 columns per invoice: invoice number, dates, seller and buyer (name, VAT ID, address, IBAN), net / VAT / gross, currency, the first five line items collapsed into a summary, detected format, source email subject/sender/date, and a processing timestamp. Missing columns are auto-created on first run, so starting with an empty tab called Invoices is fine.

Non-invoice attachments — a contract PDF, a scanned expense receipt — are skipped rather than produce garbage rows.

From the sheet onward

For DATEV I export the sheet to CSV and use the import assistant. For ad-hoc checks I filter in Sheets directly. If you'd rather land the rows in Postgres or an ERP, swap the final Google Sheets node — everything upstream stays the same.

Setup

Install n8n-nodes-invoice-api-xhub, add the credential (free sandbox keys available), connect Gmail and Google Sheets, paste your spreadsheet ID into Set Config. No activation needed — execute the workflow when you want it to run.