TradeDesk

A full-stack paper-trading platform supporting dual-market trading — US stocks and Indian (NSE) equities — with live quotes, portfolio tracking, transaction history, and strategy backtesting.

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Features

• Dual-market support
  • US stocks via Finnhub (live quotes) + Alpha Vantage (historical data)
  • Indian .NS stocks via yahoo-finance2
• Live trading simulation
  • Symbol search with debounced autocomplete merging Finnhub + Yahoo Finance results
  • Real-time OHLC quotes
  • Buy/sell with cash balance validation
• Atomic trade execution
  • All buy/sell operations wrapped in PostgreSQL transactions (BEGIN / COMMIT / ROLLBACK) to prevent partial writes
• Multi-currency architecture
  • Single INR-denominated balance
  • USD trades automatically converted to INR using live FX rates (Alpha Vantage, Redis-cached)
• Portfolio & dashboard
  • Holdings table with auto-refresh polling
  • Transaction history with currency and FX details
• Strategy backtesting
  • MA Crossover and RSI backtesting engines
  • Results persisted as JSONB
  • Supports both US and .NS historical data

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Tech Stack

Backend

• Node.js (Express, ES Modules)
• PostgreSQL
• Redis (caching: symbol search, FX rates)
• Docker

Frontend

• React (JSX)
• Vite
• Tailwind CSS v4 (CSS-first config)
• shadcn/ui (neutral base, radix primitives)
• TanStack Query
• Zustand (with persistence)
• React Router v7
• Sonner (toasts)
• Lucide (icons)

Data Providers

• Finnhub — live US quotes
• Alpha Vantage — historical US data, FX rates
• yahoo-finance2 — live and historical Indian (.NS) equities

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Architecture Highlights

• Numeric precision handling: PostgreSQL returns NUMERIC columns as JS strings. All financial math (SMA, RSI, balance arithmetic) explicitly parses these at the model layer to avoid silent string-concatenation bugs.
• Transactional integrity: Trade execution uses pool.connect() with explicit transaction blocks, ensuring no partial state is written if a trade fails mid-way.
• Currency-aware schema: transactions table stores currency, fx_rate, and inr_equivalent_total per trade; portfolio stores currency. All balances are tracked in INR.
• Symbol-aware formatting: A centralized formatCurrency(value, symbol) utility detects .NS suffixes to apply the correct currency locale across the UI.
• Resilient data sourcing: Indian market data was migrated from a stale third-party package to yahoo-finance2 after data accuracy issues were identified.

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Project Structure

TradeDesk/
├── backend/
│   ├── config/
│   │   └── schema.sql
│   ├── models/
│   ├── routes/
│   ├── controllers/
│   ├── services/
│   │   ├── trade.service.js
│   │   └── fx.service.js
│   └── index.js
└── Frontend/
    ├── src/
    │   ├── pages/
    │   │   ├── DashboardPage.jsx
    │   │   ├── PortfolioPage.jsx
    │   │   ├── TradePage.jsx
    │   │   └── BacktestPage.jsx
    │   ├── lib/
    │   │   └── format.js
    │   └── store/
    └── vite.config.js

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Getting Started

Prerequisites

• Node.js
• PostgreSQL
• Redis
• Docker (optional, for containerized services)

Environment Variables

Create a .env file in backend/ with the following:

DATABASE_URL=
REDIS_URL=
FINNHUB_API_KEY=
ALPHA_VANTAGE_API_KEY=
JWT_SECRET=

Installation

# Backend
cd backend
npm install
npm run dev

# Frontend
cd Frontend
npm install
npm run dev

Database Setup

psql -U <user> -d <database> -f backend/config/schema.sql

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Pages

Page	Description
Login / Register	User authentication
Dashboard	Stat strip + holdings table with auto-refresh polling
Trade	Symbol search, live quote, buy/sell panel, position card
Portfolio	Full transaction history with currency/FX breakdown
Backtest	Run MA Crossover and RSI strategies on historical data

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