crypto-market-data-service-guide

Crypto Market Data Service Guide

A production-ready TypeScript service for crypto market data. Features caching, rate limiting, fallback sources, and WebSocket subscriptions.

Architecture

Client Request
    │
    ▼
Rate Limiter → Cache Check
    │              │
    │          Cache Hit? → Return cached
    │              │
    │          Cache Miss
    │              │
    ▼              ▼
Primary Source (CoinGecko)
    │
    ├── Success → Cache → Return
    │
    └── Failure → Fallback Source
                    │
                    ├── CoinMarketCap
                    ├── DeFi Llama
                    └── DexScreener

Quick Start

import { MarketDataService } from '@nirholas/crypto-market-data';

const service = new MarketDataService({
  primarySource: 'coingecko',
  fallbackSources: ['coinmarketcap', 'defillama'],
  cache: { ttl: 60_000 },  // 1 minute cache
  rateLimit: { maxRequests: 30, windowMs: 60_000 }
});

Price Data

// Get current price
const price = await service.getPrice('SPA', 'usd');
// { price: 0.0123, change24h: 5.2, volume24h: 1234567 }

// Get multiple prices
const prices = await service.getPrices(['SPA', 'ETH', 'BTC'], 'usd');

// Get price with metadata
const detailed = await service.getDetailedPrice('SPA');
// { price, marketCap, volume24h, circulatingSupply, ath, athDate, ... }

Candle Data (OHLCV)

// Get 1-hour candles
const candles = await service.getCandles('SPA', {
  interval: '1h',
  limit: 100
});
// [{ time, open, high, low, close, volume }, ...]

// Get daily candles with date range
const daily = await service.getCandles('SPA', {
  interval: '1d',
  from: '2024-01-01',
  to: '2024-12-31'
});

WebSocket Subscriptions

// Subscribe to real-time price updates
service.subscribePrices(['SPA', 'ETH'], (update) => {
  console.log(`${update.symbol}: $${update.price}`);
});

// Subscribe to trade events
service.subscribeTrades('SPA', (trade) => {
  console.log(`${trade.side} ${trade.amount} @ ${trade.price}`);
});