Crypto Price Tracker

A real-time cryptocurrency price tracker for active traders — sub-second ticks, momentum-ranked gainers, a paper portfolio with live P/L, and threshold price alerts.

Features · Getting Started · Usage · Report Bug · Request Feature

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Crypto Price Tracker is an open-source, cross-platform cryptocurrency price tracker mobile app built with React Native, Expo SDK 54, and TypeScript. It streams hundreds of Bitget USDT-perpetual pairs every second, ranks the coins moving right now across 1-minute, 1-hour, and funding-rate boards, and runs a paper-trading portfolio with live unrealized P/L. Designed to feel like a precision instrument — calm under pressure, fast even on a 2 GB Android phone.

Track live crypto prices, build a watchlist, paper-trade a portfolio, and get notified the moment a coin breaks your threshold — all from one native iOS & Android app.

🚧 Active development. The core app (markets, gainers, watchlist, portfolio, alerts, coin detail) is implemented and runnable. Roadmap items below are explicitly marked.

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✨ Features

	Feature	Description
⚡	Live price tape	Sub-second ticks across hundreds of Bitget USDT-perpetual pairs, with a UI-thread flash-on-tick so you catch what just moved.
📈	Momentum gainers	Three boards — 1-minute, 1-hour, and funding rate — recomputed as ticks roll in.
⭐	Watchlist	Star any coin; persisted to AsyncStorage so it survives app restarts.
💼	Paper portfolio	Add positions with entry + quantity, see live unrealized P/L per row and across the whole book.
🔔	Threshold alerts	Configurable 24h % move + short-window % alerts via local push notifications, deduped per coin and direction.
🔍	Coin detail	Live price hero, 60-minute sparkline, momentum tiles, 24h high/low, funding rate, and watchlist toggle.
🎨	Theming	System / light / dark with persistence and semantic up/down colors tuned for contrast in both themes.
🚀	Instant cold start	TanStack Query cache persisted to AsyncStorage, so reopens show last-known prices before the first poll lands.

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🛠️ Tech Stack

Category	Technology
Framework	Expo SDK 54 + React Native 0.81 (New Architecture + React Compiler)
Language	TypeScript — strict, noUncheckedIndexedAccess, noImplicitOverride
Navigation	Expo Router 6 — file-based, typed routes
Server state	TanStack Query 5 + AsyncStorage persistence (1s refetch)
Client state	Zustand 5 — watchlist, portfolio, settings, momentum, alerts
Lists	@shopify/flash-list — 60+ FPS on a 500-row feed
Animations	Reanimated 4 + react-native-worklets
Validation	Zod 4 — portfolio input schemas
Charts	react-native-svg — custom Bezier sparkline
Notifications	expo-notifications — local threshold alerts
Surfaces	expo-glass-effect (iOS 26+) · expo-blur (iOS<26) · flat (Android)
Fonts	Inter · Space Grotesk · JetBrains Mono (tabular figures for prices)

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🚀 Getting Started

Prerequisites

• Node.js >= 20.18 (LTS)
• npm >= 10 (or pnpm / Bun)
• Xcode 16+ for iOS · Android Studio with API 35 for Android
• Expo CLI runs via npx — no global install needed

Installation

git clone https://github.com/aashir-athar/Crypto-Price-Tracker.git
cd Crypto-Price-Tracker
npm install

Run

npm start

Then, in the Expo dev server:

• Press i to open the iOS simulator
• Press a to open the Android emulator
• Or scan the QR code with Expo Go on a physical device

For full expo-glass-effect (iOS 26 Liquid Glass) parity, build a dev client with npx expo prebuild && npx expo run:ios / npx expo run:android. See zero-to-deploy.md for the full fresh-machine-to-store guide.

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📖 Usage

Run the app, then explore the bottom tabs:

npm run ios      # build & launch on the iOS simulator
npm run android  # build & launch on the Android emulator
npm run web      # web preview (best-effort)
npm run lint     # lint across the tree
npx tsc --noEmit # strict TypeScript typecheck

Typical flow once the app is open:

1. Markets — browse the full live Bitget USDT-perpetual list; tap any coin for detail.
2. Gainers — switch between 1m / 1h / funding boards to see what's moving now.
3. Watchlist — star coins to pin them; the list persists across restarts.
4. Portfolio — add a position (entry + quantity) and watch live unrealized P/L update with the tape.
5. Settings — configure threshold alerts and theme.

The data plane is a single useTickers query refetching every second; useMomentumIngest writes each tick into a rolling per-coin buffer, and useAlertsRunner checks every coin against your thresholds and fires a local notification on breach.

Swap in a different exchange (Binance, Bybit, OKX)

The app is exchange-agnostic past the client. Edit src/api/bitget.ts (or add a sibling), make it return Coin[] matching the existing shape, then point useTickers at it. Zod validates the payload, so a mismatched shape fails loudly rather than silently.

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🗺️ Roadmap

• Live ticker stream with 1s refresh
• Momentum-ranked gainers (1m / 1h / funding)
• Watchlist persisted to AsyncStorage
• Paper portfolio with live unrealized P/L
• Threshold-based push alerts (24h + short window)
• System / light / dark theme with persistence
• Coin detail with sparkline + momentum tiles
• Multi-exchange aggregation (Binance, Bybit, OKX)
• Drag-to-reorder watchlist
• Export portfolio to CSV
• WebSocket stream to replace REST polling on the foreground tab

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🤝 Contributing

Contributions are welcome — first-time contributors especially. Open an issue first for any major change.

1. Fork the repo
2. Create a branch (git checkout -b feat/your-feature)
3. Commit using Conventional Commits (feat:, fix:, chore: …)
4. Run npx tsc --noEmit && npm run lint until clean
5. Push and open a Pull Request into main

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📄 License

Distributed under the MIT License. See LICENSE for details.

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👤 Author

Aashir Athar

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If this crypto price tracker helped you, consider leaving a ⭐ — it genuinely helps the project reach more developers.

_{Built by Aashir Athar with React Native, Expo & TypeScript.}

_{Keywords: cryptocurrency price tracker · crypto portfolio tracker · React Native crypto app · Expo SDK 54 · Bitget USDT-perpetual · live crypto prices · Bitcoin Ethereum price alerts · iOS Android mobile app · TanStack Query · Zustand · TypeScript}