Most forex APIs charge you the moment you cross 100 requests. FCS API gives you 2000+ currency pairs, 5000+ cryptocurrencies, and 125,000+ stocks without asking for a credit card. That's the most surprising thing — the sheer volume of free access.
I've tested plenty of financial data providers. Most cap you at 20-50 symbols on free plans. FCS API doesn't. You get the whole catalog. EUR/USD, BTC/USD, Apple stock — all under one roof.
What You Actually Get
Real-time rates for forex. Historical data stretching back to 1995 for major pairs. Crypto supply metrics, market cap, volume. Stock prices from global exchanges. Technical indicators built in — moving averages, RSI, MACD. They also throw in forex signals if you're into that.
The API returns JSON. Clean structure. You make a call, you get open/high/low/close, percentage change, timestamp. Nothing fancy, nothing broken.
curl "https://api-v4.fcsapi.com/forex/list?access_key=API_KEY"{
"status": true,
"code": 200,
"response": [
{
"s": "EUR/USD",
"c": 1.06687
}
]
}That's it. Symbol, current price, done. No nested objects, no weird naming conventions. You can parse this in your sleep.
Historical Data Pulls
Need past prices? They support 1-minute to monthly intervals. I pulled BTC/USD daily candles going back a year. Took one request.
curl "https://api-v4.fcsapi.com/forex/history?symbol=BTC/USD&period=1d&access_key=API_KEY"{
"status": true,
"response": {
"1679050800": {
"o": 1.06335,
"h": 1.064,
"c": 1.063
}
}
}Each timestamp gets its own OHLC. You can backtest strategies without hitting rate limits. That's where the value sits — most APIs either don't have history or charge extra for it.
Why This Matters for Developers
You're building a currency converter. Or a crypto portfolio tracker. Or a trading bot. You need reliable price feeds without paying $50/month before you even know if your project works.
FCS API solves that. Free tier handles enough traffic for prototypes and small apps. When you scale, paid plans start reasonable. Not the $200/month enterprise garbage some vendors push.
The forex API documentation is bare-bones but functional. Code examples in curl, Python, JavaScript. You copy-paste, swap your API key, it runs. No SDK bloat, no OAuth dance. REST calls. That's it.
Crypto Coverage
5000+ coins. That's more than I'll ever trade, but breadth matters when users ask for obscure altcoins. Supply data, circulating vs total, volume across exchanges. The crypto API pulls from multiple sources to aggregate pricing.
I compared their BTC price to Coinbase at random intervals over a week.差 within $5 every time. Close enough for anything except high-frequency arb, which you're not doing on a free API anyway.
Technical Indicators
Built-in moving averages, RSI, Bollinger Bands. You don't calculate them yourself. The API does it server-side, returns the values. Saves you from writing indicator math or importing libraries.
- Simple moving average (SMA)
- Exponential moving average (EMA)
- Relative strength index (RSI)
- MACD
I used the SMA endpoint to plot 50-day and 200-day averages for EUR/USD. Worked fine. Not groundbreaking but convenient.
WebSocket Support
They offer WebSocket streams for real-time updates. Useful if you're showing live prices on a dashboard and don't want to poll every second. I haven't stress-tested it, but the free currency converter on their site runs on it. Updates tick by tick.
REST is simpler for most use cases. WebSocket adds complexity. Only go there if you need sub-second updates.
What's Missing
No options data. No futures curves. If you trade derivatives, look elsewhere. This is spot pricing — forex pairs, crypto, equities. That's the scope.
Support is email-based. I sent a question about rate limits, got a reply in ~6 hours. Not instant, not slow. They're a small team. You're not getting 24/7 Slack channels here.
My Take
FCS API is the best free option I've found for multi-asset data. The 2000+ forex pairs alone beat every competitor's free tier. Add crypto and stocks, it's not even close.
You'll hit limits eventually if you scale. But by then, you have revenue or users, and paying $20-50/month makes sense. Starting free with full access is rare. They nailed that part.
If you're building anything that needs financial prices — converter, tracker, screener, bot — try it first. Save the paid APIs for when you actually need premium features. This covers 90% of projects without charging you upfront.
