I've tested a lot of market data APIs. Most are either expensive, slow, or missing half the assets you need. FCS API isn't perfect but it covers more ground than anything else at this price point — forex, crypto, stocks, all in one spot.
What FCS API Actually Offers
FCS API pulls real-time and historical data for 2000+ forex pairs, over 5000 cryptocurrencies, and 125,000 stocks. That's more pairs than I'll ever trade but having them means you're not stuck when you need some obscure cross or a small-cap stock. They also serve technical indicators, conversion rates, and signals.
The big number here: 2000+ forex pairs. Most APIs give you the majors and a few exotics. FCS gives you everything, including combinations nobody asked for. If you want to build a multi-asset dashboard or test strategies across random pairs, you won't hit a wall.
Historical data goes back to 1995 for forex. Crypto coverage is newer obviously but still deep enough for backtesting. Stock data includes current prices, volume, market cap — the basics you need for screening or alerts.
How the API Works
REST API with straightforward endpoints. Authentication is simple — append your access key to the URL. No OAuth headaches. Want a list of forex symbols? One call:
curl "https://api-v4.fcsapi.com/forex/list?access_key=API_KEY"Response is clean JSON:
{
"status": true,
"code": 200,
"msg": "Successfully",
"response": [{
"id": 1,
"o": 1.06070,
"h": 1.06856,
"l": 1.06057,
"c": 1.06687,
"ch": +0.00617,
"cp": "+0.58%",
"s": "EUR/USD"
}]
}Open, high, low, close, change — standard OHLC format. No weird field names or nested arrays. You can parse this in any language without pulling your hair out.
Historical Data and Backtesting
If you're backtesting a strategy you need candles. FCS API serves historical data by period — 1 minute, 5 minutes, 1 hour, 1 day. Pull BTC/USD daily candles like this:
curl "https://api-v4.fcsapi.com/forex/history?symbol=BTC/USD&period=1d&access_key=API_KEY"Each candle includes timestamp, volume, and the usual OHLC. You get enough data to run Monte Carlo sims or train a basic ML model. Not tick-level precision but more than adequate for most retail strategies.
I've used it to backtest a mean reversion setup on EUR/USD from 2010 to 2023. No gaps, no missing days. Data quality was solid — no wild outliers or obvious errors. That matters because one bad tick can blow up your backtest results.
Crypto and Stock Coverage
Crypto side covers 5000+ coins. Bitcoin, Ethereum, the usual suspects plus a thousand tokens you've never heard of. Market cap, circulating supply, volume — it's all there. Useful if you're building a screener or tracking altcoins.
Stock data covers 125,000 tickers across global exchanges. That's every major market plus a lot of smaller ones. Real-time prices, historical candles, volume. I've tested it on US equities and it kept pace with free alternatives like Yahoo Finance. Not Bloomberg-level speed but fast enough for retail.
One thing: crypto data quality varies. Major coins are fine but obscure tokens sometimes have stale prices or missing volume. If you're trading illiquid altcoins double-check the data against an exchange feed.
Speed and Reliability
FCS API is fast. Sub-200ms response times for most calls. I've hammered it during London open — no timeouts, no rate limit errors. They say it handles thousands of requests per second and I believe it based on my stress tests.
Uptime has been solid. I've been using it for six months and only saw one brief outage during a weekend maintenance window. They post status updates but honestly most of the time it just works.
WebSocket support is there if you need live streaming data instead of polling. I haven't used it much because REST is easier for my use case but it's nice to have the option.
Pricing
Free tier gives you 500 API calls per month. That's enough to test it out or run a low-frequency trading bot. Paid plans start cheap — a few bucks a month gets you 10,000 calls. If you're serious you'll want the higher tiers but even those are reasonable compared to Bloomberg or Refinitiv.
Check the pricing page for exact numbers. They don't hide fees or charge extra for certain endpoints which is refreshing. One price, all features.
Why It Matters
Most retail traders can't afford enterprise data feeds. FCS API fills that gap. You get professional-grade data at indie developer prices. Not perfect but good enough to build real tools — charting apps, trading bots, portfolio trackers, whatever.
I've built a simple momentum scanner using their forex API. Pulls daily candles for 50 pairs, calculates 20-day returns, ranks them. Took an afternoon to set up. No fuss, no API wrapper libraries, just curl and Python. That's the appeal — it's boring in a good way.
If you need more detail on specific endpoints check the forex API docs or crypto API docs. Or just sign up and start hitting endpoints. Free tier is generous enough to figure out if it fits your needs.
