I Built Sổ Lãi, a Practical Profit Tracker for Vietnamese Online Shops

This is a submission for the GitHub Finish-Up-A-Thon Challenge What I Built I built So Lai , a local-first profit tracker for small online shops in Vietnam. The goal is simple: help a seller answer the question they often cannot answer from platform revenue alone: Is my shop actually profitable after product cost, marketplace fees, shipping subsidies, discounts, ad spend, returns, and pending COD? So Lai is not trying to be a full POS, CRM, or inventory suite. It focuses on the painful middle layer that many small sellers still manage through scattered spreadsheets: Product cost by SKU Orders from Shopee, TikTok Shop, Facebook, Zalo, or livestream sales Platform fees, shipping cost, vouchers, and discounts Ad spend by channel and SKU Return/cancellation status COD received vs. pending Net profit by order, product, and sales channel The app runs locally with Node.js and JSON storage, so it does not require paid APIs or cloud setup. GitHub repo: https://github.com/klauski24/so-lai Demo Run locally: git clone https://github.com/klauski24/so-lai.git cd so-lai npm start Open: http://127.0.0.1:4182 What the demo shows: A Vietnamese-language dashboard called Sổ Lãi Shop profile setup Clear explanation of where the numbers come from CSV import for products, orders, and ad costs Manual order entry Profit analysis by channel and SKU Alerts for loss-making products, high COD pending, and high return rate CSV and Markdown report export Screenshots are included in the repository: so-lai-desktop.png so-lai-mobile.png The Comeback Story The first version was too vague. It started as an English-named dashboard called ProfitLens . It had some useful calculations, but it did not feel practical yet. The biggest problems were: The app used Vietnamese currency but had an English product name. There was no place to define the shop. It was not clear where the data should come from. The dashboard looked like a demo, not something a seller could actually use. I reworked the project into So