How to Log Invoice Receipts from Gmail to Google Sheets with N8n

Workflows > New > Gmail Trigger

Connect Gmail to N8n

Set up Gmail trigger to monitor for new emails matching your invoice criteria. You'll authenticate with OAuth and configure the search filter.

1. 1Click the + button to add a new node
2. 2Search for 'Gmail' and select 'Gmail Trigger'
3. 3Click 'Create New' under Credentials
4. 4Authorize with your Google account and copy the credentials

Gmail Trigger > Parameters

Configure Email Filter

Set up the Gmail trigger to only fire on emails containing invoices. Use Gmail's search operators to filter by sender domain or subject keywords.

1. 1Set Event to 'Message Received'
2. 2In the 'Query' field, enter 'subject:invoice OR subject:receipt OR from:billing@'
3. 3Set 'Poll Times' to 'Every 5 minutes'
4. 4Enable 'Include Attachments'

Gmail Trigger > + > Extract From File

Add Text Extraction Node

Extract invoice data from email body or PDF attachments. N8n's Extract From File node handles PDF parsing automatically.

1. 1Add a new node and select 'Extract From File'
2. 2Set 'Binary Property' to 'attachment_0'
3. 3Choose 'PDF' as file type
4. 4Enable 'Extract Tables' option

Extract From File > + > Code

Parse Invoice Fields

Use a Code node with regex or string parsing to extract specific invoice fields like amount, date, and vendor name from the raw text.

1. 1Add a 'Code' node after the extraction
2. 2Set Language to 'JavaScript'
3. 3Paste the invoice parsing code in the editor
4. 4Map input data from previous node

Code > + > Google Sheets

Connect Google Sheets

Authenticate with Google Sheets and select your financial tracking spreadsheet. N8n will need edit permissions to append new rows.

1. 1Add 'Google Sheets' node
2. 2Select 'Append' operation
3. 3Create new Google credentials if needed
4. 4Choose your target spreadsheet and worksheet

Google Sheets > Parameters > Values to Send

Map Invoice Data to Sheet Columns

Configure which parsed invoice fields go into which spreadsheet columns. Set up proper data formatting for dates and currency amounts.

1. 1Set 'Data Mode' to 'Define Below'
2. 2Map 'Date' field to column A using {{$node["Code"].json["date"]}}
3. 3Map 'Vendor' to column B and 'Amount' to column C
4. 4Add 'Invoice Number' and 'Email Subject' mappings

Code > Settings > Continue on Fail

Add Error Handling

Configure what happens when PDF parsing fails or required invoice fields are missing. Set up fallback behavior and error notifications.

1. 1Click the Code node and select 'Settings'
2. 2Set 'Continue on Fail' to true
3. 3Add an 'IF' node after Google Sheets
4. 4Configure condition: {{$node["Code"].json["amount"]}} exists

Code > + > Google Sheets (Read) > IF

Set Up Duplicate Prevention

Prevent the same invoice from being logged twice by checking existing Google Sheets rows for matching invoice numbers or email message IDs.

1. 1Add 'Google Sheets' node with 'Read' operation before the append node
2. 2Search existing rows for matching invoice number
3. 3Add 'IF' node to check if invoice already exists
4. 4Route new invoices to append, duplicates to ignore

Workflow > Execute Workflow

Test with Real Invoice Email

Send a test invoice email to your Gmail account and verify the workflow extracts fields correctly and logs to the right spreadsheet rows.

1. 1Click 'Execute Workflow' button
2. 2Send a test email with invoice PDF to your Gmail
3. 3Wait 5-10 minutes for Gmail trigger to fire
4. 4Check execution log and verify Google Sheets row was added

Workflow > Settings > Active

Activate and Monitor

Turn on the workflow for production use and set up monitoring to catch parsing errors or API failures. Review execution logs weekly.

1. 1Click the 'Active' toggle in top right
2. 2Set up webhook notifications for failed executions
3. 3Configure workflow to run every 5 minutes
4. 4Add execution data retention settings

Drop this into an n8n Code node.

// Enhanced invoice amount parsing that handles multiple currency formats
const text = items[0].json.extractedText;
const patterns = [

// Enhanced invoice amount parsing that handles multiple currency formats
const text = items[0].json.extractedText;
const patterns = [
  /(?:total|amount due)[:\s]+\$?([\d,]+\.\d{2})/i,
  /\$([\d,]+\.\d{2})\s*(?:total|due)/i,
  /([\d,]+\.\d{2})\s*USD/i
];

for (const pattern of patterns) {
  const match = text.match(pattern);
  if (match) {
    return [{json: {amount: parseFloat(match[1].replace(/,/g, ''))}}];
  }
}
return [{json: {amount: null}}];