n8n Expense Triage Workflow: Forms to Google Sheets & Gmail

Automatically triage employee expenses from Forms into Google Sheets—and notify the right people by Gmail

This n8n Expense Triage Workflow captures each expense submission via n8n Form Trigger, checks for duplicates in Google Sheets, classifies entries by review status, and sends an employee Gmail receipt—while alerting a reviewer only when an expense needs attention.

What this workflow does

• Captures submissions: An n8n Form Trigger captures each employee expense as it’s submitted.
• Normalizes and de-duplicates: The workflow normalizes the submission, creates a duplicate key using employee email + date + vendor + amount, and checks the Google Sheets data for repeat submissions.
• Routes with clear review rules: A Switch node routes every expense:
  • Invalid amounts → marked Needs Correction
  • Amounts above the USD 500 threshold or possible duplicates → marked Needs Review
  • Clean small expenses → marked Pending Review
• Writes results back to Sheets: Appends each expense row with review_status and review_reason.
• Emails the right notifications: The employee always receives a Gmail receipt; the reviewer is alerted only for expenses requiring attention.
• Keeps humans in control: Approval and reimbursement decisions remain with your team.

Use cases

• Small businesses triaging expense claims currently handled by hand in spreadsheets.
• Teams validating expense amounts and flagging entries over USD 500 for extra scrutiny.
• Organizations that want duplicate detection and consistent intake without changing their existing review process.

Technical details

• Tech stack / nodes: if, set, gmail, switch, sticky note, form trigger
• Integrations: Google Sheets (append + duplicate checks) and Gmail (employee receipt + reviewer alerts)
• Setup essentials: Import the workflow JSON, connect Google Sheets and Gmail credentials, create a sheet with these 11 headers in row 1: submission_id, employee_email, expense_date, vendor, amount, currency, description, submitted_at, review_status, review_reason, duplicate_key
• Requirements: n8n supporting Form Trigger 2.6, Google Sheets 4.7, Gmail 2.2; a Google account with Sheets and Gmail access.
• Customization: Adjust the USD 500 threshold in Check Expense Amount and update the duplicate-key fields if needed.