Real-Time KRW Exchange Rate API: Korean Finance Data for Trading Bots

#api #webdev #tutorial #korea

The KRW/USD exchange rate moves 1-2% daily. If your trading bot or fintech app uses a hardcoded rate or a stale API, you're making decisions on wrong data. Here's how to get real-time Korean exchange rate data via API.

Why Exchange Rate APIs Fail for Korea

Most generic FX APIs have these Korea-specific gaps:

Rate lag of 15+ minutes during volatile Korean market sessions
Missing KRW cross-rates against crypto (BTC/KRW, ETH/KRW)
No access to the "Kimchi premium" (BTC/KRW vs BTC/USD spread)
Seoul market hours (09:00-15:30 KST) not reflected in rate freshness

Real-Time KRW Rates

import requests

API_KEY = "your-key"

# Get current KRW exchange rates
resp = requests.get("https://api.lazy-mac.com/k-exchange-rate",
    params={"base": "KRW", "targets": "USD,EUR,JPY,BTC,ETH"},
    headers={"Authorization": f"Bearer {API_KEY}"}
)

rates = resp.json()
# {
#   "base": "KRW",
#   "timestamp": "2026-04-10T02:30:00Z",
#   "freshness_seconds": 12,
#   "rates": {
#     "USD": 0.000723,  # 1 KRW = $0.000723
#     "EUR": 0.000668,
#     "JPY": 0.1089,
#     "BTC": 0.0000000138,
#     "ETH": 0.000000245
#   }
# }

Historical Rate Data

# Get 30-day KRW/USD history for backtesting
resp = requests.get("https://api.lazy-mac.com/k-exchange-rate/history",
    params={
        "pair": "KRW/USD",
        "from": "2026-03-10",
        "to": "2026-04-10",
        "interval": "1h"  # 1m, 5m, 1h, 1d
    },
    headers={"Authorization": f"Bearer {API_KEY}"}
)

candles = resp.json()["candles"]
# [{"timestamp": "2026-03-10T09:00:00Z", "open": 0.000720, "high": 0.000728, ...}, ...]

Kimchi Premium Tracker

# Get the BTC premium in Korean exchanges vs global
resp = requests.get("https://api.lazy-mac.com/k-exchange-rate/kimchi-premium",
    headers={"Authorization": f"Bearer {API_KEY}"}
)

premium = resp.json()
print(f"BTC Kimchi Premium: {premium['premium_pct']:+.2f}%")
# "BTC Kimchi Premium: +2.34%"

Trading Bot Integration

import asyncio

async def get_rate_with_fallback(pair: str) -> float:
    """Get exchange rate with automatic fallback on stale data."""
    resp = requests.get(f"https://api.lazy-mac.com/k-exchange-rate/live",
        params={"pair": pair, "max_age_seconds": 30},
        headers={"Authorization": f"Bearer {API_KEY}"}
    )

    data = resp.json()
    if data["freshness_seconds"] > 30:
        # Data is stale, raise alert
        raise StaleDataError(f"Rate data is {data['freshness_seconds']}s old")

    return data["rate"]