Project #000001: From REA to a working QuickBooks-style desktop app (Mac + Windows)

[lxistired]

I used REA to investigate QuickBooks Desktop for Mac 2024 Trial and built Ledger Reborn, an independently implemented open-source accounting app. It saves actual SQLite journals, invoices, inventory movements and recorded payments, and calculates its reports.

Source: https://github.com/lxistired/ledger-reborn
Desktop preview/downloads: https://github.com/lxistired/ledger-reborn/releases/tag/v2026.10.12-preview.1
Maintainer / future projects: @lxistired

What REA contributed

REA/Ghidra helped inspect focused native paths around inventory arithmetic, budget signs, reconciliation balances and cash-basis branches. Its resource decoder supplied NIB control/layout facts; native observation established selected window layouts and actions. I used those findings to guide independent implementation, then checked the accounting outputs separately.

The investigation and reconstruction details are in the case study. REA supplied evidence and imperfect pseudocode; it did not recover the whole original source or generate a complete product in one step.

What works

Balanced journals; customers/vendors and contact snapshots; service/inventory invoice and bill lines; partial and allocated payments; moving-average inventory; CSV bank import/dedup/matching/classification/reconciliation; financial reports, budgets, period locks and backups. Everything is local and the implemented workflows need no Intuit account.

The public synthetic suite has 52 tests, the HTTP smoke has 12 checks, and each packaged executable runs a separate 8-check frozen smoke. These are separate scopes, not a count of reconstructed UI features. The screenshot above is an actual independent macOS window. All three native builds passed: Windows x64 (setup executable and portable ZIP), Apple Silicon macOS and Intel macOS (DMGs). The release links the actual successful CI run and includes packaged-executable evidence and checksums. Apple Silicon received a separate local native-window check; full manual Windows/Intel GUI and installation checks remain open.

A separate local official-sample comparison matched three original reports account-by-account to the cent. Those vendor sample files are not redistributed; this does not establish restored invoice/SKU/payment history or full migration.

Boundaries and next steps

This is a calendar-versioned preview, 2026.10.12-preview.1. Full pixel/interaction equivalence has not passed. Payroll, filing, live bank/payment services, multicurrency, credit memos and returns are not included. Original binaries, proprietary images and sample databases are not shipped. Preview packages do not have Apple Developer ID/notarization or a Windows publisher certificate; Windows requires WebView2. The project has no affiliation with Intuit or endorsement from REA.

I intend to maintain the project in public through the accounting maintenance tracker. Project #000002 — personal tax is on the roadmap, not already working software. If you want to follow the series, follow @lxistired.

Feedback and contributions are welcome, especially independent accounting edge cases, repeatable original-workflow comparisons and installation checks. I hope this is a useful example of moving from REA evidence into a runnable application with explicit validation limits.