Funds Grid

01Project

What the system is

Funds Grid is a multi-user portfolio tracker for Pakistani retail investors, covering PSX-listed stocks, ETFs and mutual funds. I designed and built it end to end on my own time: the Next.js frontend, the NestJS API and the data model behind them.

02Problem

What needed solving

Investors who hold shares through a broker and mutual funds through several fund managers only ever see one statement at a time. None of them shows a combined cost basis, realised and unrealised profit, dividend income after withholding tax, or how the whole portfolio compares with the KSE-100.

03My role

What I was responsible for

• Designed the data model for portfolios, holdings, transactions, cash movements and daily price history, built with Prisma on MySQL.
• Built the NestJS API in controller, service and repository layers, with session auth and ownership guards on every portfolio, asset and transaction.
• Built the Next.js frontend as a backend-for-frontend, so the browser never calls the API directly.
• Integrated a market-data provider for prices, fund NAVs, the KSE-100 index, dividend payouts and corporate announcements.
• Wrote reconciliation tests and a read-only diagnostic that check the portfolio figures against accounting invariants.

04Engineering

What I built

1. 01

   Transaction engine

   Buys, sells, dividends and cash movements are replayed in order to derive weighted average cost and realised profit, and a sale can never exceed the quantity held.

2. 02

   Tax by filer status

   Capital gains tax on each sale and withholding tax on each dividend are worked out at the investor's filer or non-filer rate.

3. 03

   Dividend Center

   Announced payouts are matched to the shares each investor holds, then confirmed, snoozed or marked as not received.

4. 04

   KSE-100 benchmark

   Time-weighted return, alpha, volatility and maximum drawdown against the KSE-100 for portfolios that hold stocks or ETFs.

5. 05

   Admin console

   User management, data sync triggers and targeted push notifications, with every account action written to an audit log.

6. 06

   Installable app

   A progressive web app that installs on a phone, with web push notifications and an offline fallback page.

05Technologies

How the pieces fit

06Complexity

Engineering challenges

• Cost basis, realised profit and tax all come from replaying the transaction history, so entries recorded out of order or on the same day must still produce the same result.
• Portfolio totals must satisfy accounting identities, such as total value minus net invested capital equalling unrealised plus realised profit plus dividends, within a defined rounding tolerance.
• Prices for funds, stocks and the index arrive from an external provider and are stored as daily history, so every valuation has to show how fresh its price is.
• No investor may read or change another's portfolios, so ownership is checked on every route, including for soft-deleted records.