The “Glass Box” AI Accounting System

CLIENT / ROLE

Lead Developer & Architect

YEAR

2023 - Current

TECHNOLOGY

Core Engine: Google Apps Script (GAS), Intelligence: Google Gemini (via API) , Database & UI: Google Sheets, Storage: Google Drive

AI Accounting

Project Overview

1. Background: The “Data Gap” in Modern Accounting

For decades, automated accounting relied heavily on bank feeds and credit card statements. While efficient, this method created a “Data Gap”: it captured when money was spent and who was paid, but it rarely captured what was bought or the tax evidence required for audits.
To bridge this gap, businesses traditionally hired humans to manually type data from receipts into software—a process that is slow, error-prone, and expensive.
This project was born from the realization that modern Large Language Models (LLMs) have finally solved the “unstructured data” problem. By combining ubiquitous cloud storage (Google Drive) with capable AI (Gemini), we can now process the “hard” data (receipts and invoices) first, rather than treating them as an afterthought.

 

2. Objective

The primary goal of this application is to automate the extraction, categorization, and reconciliation of financial documents into a double-entry accounting system.
Crucially, the objective is not to remove the human accountant, but to elevate them. Instead of acting as a data entry clerk typing numbers from a PDF, the user acts as a “Reviewer,” approving or rejecting the AI’s work. The system aims to reduce the time from “shoebox of receipts” to “Balance Sheet” by 80-90%, while maintaining strict audit trails.

 

3. Intended Users

  • Micro-Enterprises & Freelancers: Who need tax-compliant books (especially in jurisdictions like Japan with specific invoice registration requirements) but cannot afford enterprise ERPs.
  • Boutique Accounting Firms: Who need a lightweight, customizable tool to process client receipts rapidly without navigating complex SaaS interfaces.
  • Developers/Founders: Who require a “transparent” financial stack where they own the data and the logic, rather than locking it inside a proprietary ecosystem.

 

4. Core Functionality & User Experience

The application is designed around a “Human-in-the-Loop” workflow. It handles the heavy lifting of data extraction, leaving only the high-value decision-making to the user.

  • Seamless Ingestion:
    The user experience begins simply: dropping a digital receipt or invoice into a designated Google Drive folder. There are no forms to fill out or manual uploads required. The system automatically detects new files and queues them for processing.
    Intelligent Extraction & Context Awareness:
  • Instead of just looking for dates and totals, the AI reads the document like a human would. It extracts the vendor, analyzes the line items to determine the nature of the expense, and identifies critical compliance data—such as Invoice Registration Numbers for tax deductions.
  • Visual Verification (The “Traffic Light” Interface):
    Rather than blindly trusting the AI, the interface presents the data in a clear, spreadsheet-based review pane.
  • One-Click Posting & Audit Trail:
    Once the user reviews and approves the batch, a single click finalizes the process. The system writes the double-entry journals to the database and, critically, performs “digital housekeeping.” It renames the original source files with unique IDs and moves them to a secure archive folder. This ensures that every dollar in the financial reports can be instantly traced back to a specific, organized source document.
  • Real-Time Financial Visibility:
    Because the system is built on a live database, financial reports are never stale. Users can generate Balance Sheets and Profit & Loss statements on demand, giving them an immediate, accurate picture of their financial health without waiting for month-end close procedures.

 

5. What Makes This Application Unique?

While there are many AI accounting tools on the market, this application hits on a few unique notes in the current landscape:

A. The “Glass Box” Philosophy

Most SaaS tools are “Black Boxes”—you upload a file, and a result pops out. If it’s wrong, you don’t know why. This application is a “Glass Box.” It explicitly exposes the AI’s “Confidence Score” and “Feedback” directly to the user. If the AI is unsure, it explains why. This transparency builds trust and allows the user to calibrate the system over time.

B. “Settlement-Agnostic” Architecture

By focusing on the Receipt as the primary source of truth (rather than the bank feed), the system creates a higher standard of audit proof. It captures the tax details and line items that bank feeds miss, positioning it closer to enterprise ERP workflows than typical SMB tools.

C. Low-Code / High-Power

This project demonstrates that you don’t need a massive AWS infrastructure to build powerful fintech tools. By leveraging the existing Google Workspace ecosystem (Identity, Storage, Compute), we built a secure, scalable, and practically free-to-run ERP system.