How to Build a Wallet Management System – Claude Code + Google Apps Script + Google Sheets

Any business that holds other people's money needs one source of truth, or it loses money to disputes. This is a complete wallet management system on Google Sheets: users add funds, request withdrawals and place orders that debit their balance, while an admin approves every single movement with the proof attached.

What it does

A user tops up by choosing an amount, picking one of the bank accounts you have published (with its QR code), paying, then submitting the transaction ID and a screenshot of the slip. That lands in the admin's wallet queue, where you can open it, check the reference against your actual bank, and approve or reject — approval credits the balance instantly. Withdrawals run the same loop in reverse: the user requests against a payment method they have saved, you approve singly or in bulk, upload your own payment proof, and the balance is debited. Nothing moves without a record on both sides.

Highlights

• You decide which payment methods users may add — bank transfer, mobile wallet, digital wallet — and nothing outside that list is accepted
• Orders created for a user can auto-debit their wallet, with tracking ID, delivery partner, status and an attached invoice or PDF
• Manual credit and debit adjustments for the cases that fall outside the normal flow
• A reconciliation view, and a print report in every section
• Direct one-to-one chat: each user talks only to the admin, the admin talks to everyone
• Per-user colour themes, dark and light mode, and branding applied across the portal
• SWR caching, so moving between sections is instant rather than a reload

Built with Claude Code

The system was generated in ten prompts using Claude Code in VS Code, built in chunks rather than in one pass, then deployed to Apps Script. All ten prompts are included, along with the demo-data function that creates every sheet so the app works the moment it is deployed.

Who it is for

Resellers, courier and logistics operators, coaching platforms, buying agents — anyone who holds a customer float and currently tracks it in a spreadsheet where the balance and the bank keep disagreeing.