Freeze POS: Offline-First Point of Sale

Overview

Freeze is a desktop point-of-sale and back-office application built for African small and medium businesses operating in low-connectivity environments, where cloud SaaS simply isn't an option. Invoicing, inventory, cash management, receivables, purchasing and industry add-ons all live in one Electron app that stays fully operational with no network. It was first deployed in Congo-Brazzaville and designed to be localized to other markets.

Freeze is your register, your stock and your cash, even with no internet.

It is intentionally not a distributed multi-store cloud ERP and not an accounting suite. It does one thing seriously: run a real business's daily operations on a local machine, correctly, offline.

The engineering challenge

The hard part of Freeze is twofold: doing money, stock and tax correctly with no cloud to fall back on, and keeping a system that deep simple enough to master in an afternoon. Both forces shaped every decision:

Offline-first by design. The app boots, sells, prints and reports with zero connectivity. The network is only used opportunistically (license heartbeat, encrypted backups, cloud reporting sync).
Powerful, yet usable in about 2 hours. Freeze spans POS, stock, cash, tax and six business add-ons, but it's designed to be installed and used like an expert within a couple of hours, not after days of training. Modules activate only when a business needs them, settings ship with sensible defaults, each role gets its own tailored screen, and realistic demo data can be loaded to learn on before going live.
Correctness over shortcuts. Multi-rate VAT (18% / 5% / exempt) plus the Congolese centime additionnel, FIFO lot costing, cash-session reconciliation and receivables aging (0 to 30, 31 to 90, 90+ days) are enforced in the domain layer, not left to the UI. A fiscal-declaration report reconciles taxable base, collected VAT and additional tax for filing.
A strict IPC contract. Every capability exposed to the UI flows through five enforced layers (service, IPC handler, preload, typed bridge, store/page), validated in CI so the renderer can never call an unsafe or untyped path.

Key capabilities

Sales & invoicing

POS invoicing with configurable VAT and additional tax
Quotes / proformas with one-click conversion to invoice
Credit notes with automatic stock re-integration
Customers, credit limits, receivables and collections
Wholesale / retail pricing, managed discounts, sales orders and delivery notes

Inventory & purchasing

Product and service catalog with hierarchical categories
Multi-warehouse stock with inter-warehouse transfers, all on one offline instance
Stock entries (draft to validation), FIFO lots, physical inventories
Purchase orders, supplier invoices, payables tracking

Cash & treasury

Multi-register support with open/close sessions, float and FCFA cash counting
Collections, deposits, withdrawals and expenses
Payment methods: cash, card, mobile money, cheque, bank transfer

Setup & configuration (the differentiator)

Guided first-run setup: configure the database and company once, then start selling
Deep but friendly settings for company, users & roles, warehouses, registers, stock and POS behavior, all with sensible defaults
Activate only the modules a business actually uses; everything else stays out of the way
Load realistic demo data to train staff and explore the app before going live

Reporting & dashboards

Role-based dashboards: a dedicated home screen per role (admin, cashier, accountant, stock manager) surfacing only what that person needs
Online reporting: the app runs fully offline, yet its data syncs one-way to the cloud whenever internet is available, so owners can review their reports online from anywhere without the app ever depending on a connection
Multi-channel revenue analysis (products, restaurant, car wash, bar, delivery), payment mix, per-establishment P&L
Gross-margin analysis by product and channel, top products, customer profitability
Sales / stock / cash journals, receivables & payables aging
Fiscal declaration: VAT by rate and additional-tax summaries for filing

Activatable business add-ons

Modules that switch on per business, living inline in the codebase rather than as bolt-on plugins:

Service providers: commissions and payouts (car washers, mechanics, waiters, and more)
Car wash: station tickets linked to the register
Restaurant / lounge: zones, tables, service tickets, kitchen flow
Delivery: delivery tickets, cash-on-delivery, driver assignment
Subscriptions: client plans and contracts
Garage: customer vehicles and history

Platform engineering

Offline RSA license with device fingerprint, plus an API heartbeat when internet is available
Scheduled encrypted backups
Resilient cloud reporting sync: a durable outbox that survives app kills, acknowledges only on success, and retries with exponential backoff when offline
Server / LAN client mode: pair additional terminals to one instance over the local network
Data-integrity diagnostics and support bundles for field troubleshooting

Localization, done properly

Freeze isn't generically "internationalized." It's localized to how business is actually run on the ground: configurable currency and tax rules, multi-rate VAT plus region-specific levies, denomination-aware cash counting, and a French-first UI. The first locale is Congo-Brazzaville (FCFA, 18% VAT plus the 5% centime additionnel, cash denominations from coins to 10,000 notes), and the tax and currency model is built to extend to other markets.

Tech stack

Electron (electron-vite) · React 19 · TypeScript · Tailwind CSS v4 · Zustand · MySQL 8 · Drizzle ORM · Zod · Recharts · ExcelJS · Vitest · GitHub Actions CI (lint, typecheck, IPC-contract checks, unit + zero-to-current MySQL migration tests).

What I worked on

Product and technical design of an offline-first desktop application: the domain model for invoicing, stock and cash; the enforced IPC contract between the Electron main process and the React UI; the MySQL/Drizzle schema with tested migrations; and localization to Congolese tax and cash rules. The emphasis throughout was correctness and resilience on a single offline machine rather than cloud scale.