How to Build Income Expense System in Google Sheets with AI (2026) - E46

A complete income and expense management system built on Google Sheets and Apps Script, with a React web app on top. Every amount coming in or going out is entered against a department, a category and a payment method, then routed through an approval workflow — so the books stay controlled instead of turning into a shared sheet that everyone edits.

What it does

Users submit income or expense entries; admins approve them, reject them with a mandatory remark, or send them back for resubmission. Budgets are set per department and the system blocks entries that would push spending past the limit. Receipts go out over WhatsApp or email using templates you control, with 18 dynamic placeholders filled from the transaction. Gemini AI sits on the same data — it writes financial reports, answers questions through a chatbot, flags anomalies such as duplicate or unusually large transactions, and forecasts next month's income and expense.

Highlights

• Approval workflow with approve, reject and resubmit states
• Budget control that stops overspending before it is posted
• Gemini AI reports, chatbot, anomaly detection and forecasting
• WhatsApp and email receipts from customizable templates
• Three roles with department-level access control
• Department, category, payment method and contact masters
• Notifications and a full activity log for the audit trail
• Mobile-responsive React interface — no server or hosting needed

Who it is for

Trusts, NGOs, mosques, schools and small businesses that need a proper approval trail on money movement but want to stay inside Google Sheets. It is also a solid starting point for developers building any Apps Script finance dashboard, since the sheet is the database and the whole system is two files.