Spending emails in Gmail logged to a Google Sheet by AI

Spending emails in Gmail logged to a Google Sheet by AI

An n8n workflow that turns spending emails into rows in a Google Sheet. It watches two Gmail labels, one for invoices and one
for payment notices, and opens any PDF attached to them. An AI model then reads each email and returns the date, the
service, the details, the amount, the category and the currency. Each payment becomes one row.

What is inside

• workflow.json: the workflow as n8n exports it, twenty-four nodes. Three are sticky notes. It holds no credential.
• README.md: these notes.

What we changed from the original copy

• The Gemini chat model asked for gemini-1.5-flash, which Google's model pages no longer list. Google Gemini Chat Model1
  now asks for gemini-3.8-flash, Google's current Flash model.
• The Groq chat model asked for llama-3.2-11b-text-preview. Groq's deprecation page says that model was replaced by an
  11B vision model, which was shut down in April 2025. Groq Chat Model now asks for llama-3.3-70b-versatile, which
  Groq's models page lists for production.
• The two Gmail label ids, the password for the PDFs and the address of the author's Google Sheet are gone. They are now the
  placeholders <YOUR_INVOICE_LABEL_ID>, <YOUR_PAYMENT_LABEL_ID>, <YOUR_PDF_PASSWORD> and <YOUR_SHEET_ID>.
• Switch held the sender addresses of the author's own banks. Its rules now hold the placeholders
  <YOUR_MULTI_PAYMENT_SENDER> and <YOUR_SINGLE_PAYMENT_SENDERS>.
• The prompt of Extract details named one bank. It now says that 0 means an email with several payments and 1 means an
  email with one payment.
• The card field listed the author's card names and their last digits. It is now free text, so the model writes the card
  as a short name with four digits, or null.
• The Google Sheets tab is called Expenses. The original pointed at a tab by its number.
• The credential names, which held an email address, are gone.

Before you start

• A Gmail account with two labels, one for invoices and one for payment notices. A Gmail filter can apply each label to
  the right mail on its own.
• A Google Gemini API key and a Groq API key.
• A Google Sheet with a tab called Expenses. Row 1 holds these eight names: date, service, details, amount,
  category, currency, payment and source. If one is missing, the sheet step stops and says the column names were
  updated.

Set it up

1. In n8n, create a workflow, open its menu and choose Import from File. Pick workflow.json.
2. In Get invoice and Get payment, add your Gmail OAuth2 credential and pick the matching label. This replaces the
   two label placeholders.
3. In Switch, replace <YOUR_MULTI_PAYMENT_SENDER> with the address that sends mail listing several payments, such as a
   daily card summary. In the other two rules, replace <YOUR_SINGLE_PAYMENT_SENDERS> with the senders of one-payment
   mail, separated by |.
4. If your PDFs are protected, replace <YOUR_PDF_PASSWORD> in Extract invoice and Extract payment. Otherwise the
   placeholder text is passed on, and an unprotected PDF ignores it.
5. Add a Google Gemini credential in Google Gemini Chat Model1 and a Groq credential in Groq Chat Model.
6. Add a Google Sheets OAuth2 credential in Send and Send1, and replace <YOUR_SHEET_ID> in both with your sheet's id,
   the part of its address between /d/ and /edit.
7. Publish the workflow. The two triggers check Gmail every minute.

How a run goes

1. Get invoice and Get payment pick up new mail with their label and download its attachments. Extract invoice and
   Extract payment read the first attachment as a PDF. An email with no attachment carries on without it.
2. Invoice data and Payment data join the email's text and the PDF's text. Switch then sorts the mail by sender.
3. Mail from the multi-payment sender goes to HTML, which picks every element with the class spend-table. Split Out
   makes one item for each, and Set data 0 marks it as type 0.
4. Mail from the one-payment senders goes to Set data 1, type 1. Both paths meet in Merge and go to Extract details.
   Gemini reads the email and returns the fields, and Send appends the row, with the card in the payment column.
5. All other mail goes to Set data 2 and Extract details1. Groq reads it, and Send1 appends the row with an empty
   payment.

Change the result

• Which mail goes where: the three rules in Switch.
• Which element holds one payment in a multi-payment email: the selector .spend-table in HTML.
• The categories, the currencies and the other fields: the schemas in Structured Output Parser and
  Structured Output Parser1.
• How the model reads the mail: the messages in Extract details and Extract details1.
• The columns: the mapping in Send and Send1, and row 1 of your tab.

Good to know

• Until you fill in the sender placeholders in Switch, no mail matches the first two rules, so all mail takes the invoice
  path and the Groq model.
• The email text and the PDF text go to Google for Gemini and to Groq. Check what your labels collect before you turn
  the workflow on.
• Each email costs one model call. A multi-payment email costs one for each payment it holds.
• The source column always holds the word n8n.
• A limit in your Gemini or Groq plan can stop a run. The two extraction chains and the two sheet nodes try again after a
  failure.
• The HTML selector only works when the sender marks each payment with that class.
• Mindket did not run this workflow against Gmail, Gemini, Groq or Google Sheets. These notes follow n8n's published node
  code and the providers' own pages, read on 12 November 2026.