Developers keep searching for the same set of questions about currency APIs, exchange rate APIs, and forex APIs: which ones are free, which are reliable, what Xe costs, whether Google has an API, how to build a converter in Python. We pulled the 20 most-asked from Google's People Also Ask and answered each one directly — no fluff, no affiliate padding.
Q1.Is there a free API for currency conversion?
Yes — several. The main free options in 2026:
- Frankfurter — 100% free, no API key, ECB daily reference rates for ~30 currencies, historical back to 1999.
- fawazahmed0/currency-api — free via jsDelivr CDN, 200+ currencies including crypto.
- ExchangeRate-API — 1,500 requests/month on the free tier (key required).
- freecurrencyapi.com — 5,000 requests/month.
- AllRatesToday — free plan with hourly updates, suitable for production workloads.
For deeper coverage of the trade-offs, see our developer guide on free currency APIs.
Q2.What is a currency API?
A currency API is a REST web service that returns exchange rates between currencies, usually as JSON. A typical call:
GET https://api.allratestoday.com/v1/rates?source=USD&target=EUR
→ [{"rate": 0.85, "source": "USD", "target": "EUR", "time": "2026-04-19T12:00:00Z"}]Currency APIs power e-commerce checkout, finance dashboards, accounting tools, travel apps, international payroll, and any software that displays money in more than one currency. Full background in What is a currency API?.
Q3.What is a forex API?
A forex (FX) API is a currency API built for trading rather than display. Expect:
- Tick-level bid/ask quotes with millisecond latency (not just a mid-market rate)
- Historical OHLC (open/high/low/close) data for charting
- Sometimes order execution endpoints — place, modify, cancel
Examples: OANDA, MetaTrader (MT4/MT5), TraderMade, Polygon.io, FXCM. General-purpose currency APIs only return reference mid-market rates and are not suitable for trading.
Q4.What is an FX API?
"FX API" is another name for "forex API." Some enterprise providers — banks, Stripe's FX product, Bloomberg, OCBC — reserve "FX API" for streaming quotes and execution services covering 100+ pairs. In casual developer conversation, "currency API" and "FX API" are often used interchangeably.
Q5.What is an open exchange rate?
Two meanings:
- Generic: an exchange rate openly accessible through a public API — no private contract needed.
- Specific: Open Exchange Rates is the name of a commercial provider publishing rates for 200+ currencies since 2011. Free tier: 1,000 requests/month, hourly updates, USD base only.
Q6.Is the Frankfurter API free?
Yes. Frankfurter is a free, open-source currency data API with no key, no signup, and no documented rate limit for normal use. It tracks ~30 currencies using European Central Bank daily reference rates and supports historical data back to 1999. Because it's ECB-based, rates update once per business day around 16:00 CET — great for accounting and display, not for trading.
Q7.Is an exchange rate API free?
Depends on the provider:
| Provider | Free tier | Key? |
|---|---|---|
| Frankfurter | Unlimited | No |
| fawazahmed0 | Unlimited | No |
| AllRatesToday | Free plan, hourly updates | Yes |
| ExchangeRate-API | 1,500/mo | Yes |
| freecurrencyapi.com | 5,000/mo | Yes |
| Open Exchange Rates | 1,000/mo | Yes |
| Fixer.io | 100/mo | Yes |
| Xe / OANDA / Bloomberg | None | Yes |
See Best free currency exchange API (2026) for a detailed comparison.
Q8.Is ExchangeRate-API free?
ExchangeRate-API has a free plan of 1,500 requests/month, no credit card required. Fine for hobby projects, prototypes, and small internal tools. The terms of service explicitly ask commercial users to upgrade — so it's not positioned for production traffic.
Q9.How much does ExchangeRate-API cost?
Paid plans as of 2026:
- Pro — $13.99/month, 30,000 requests/month, hourly updates
- Business — $29/month, 100,000 requests/month
- Volume — $49/month, 1.5M requests/month, minute-level updates
- Enterprise — custom
Prices change occasionally; check their pricing page for current numbers.
Q10.Does Xe have an API?
Yes. Xe Currency Data API provides real-time and historical exchange rates for 170+ currencies. It's used by Fortune 500 companies, banks, and fintechs, with optional SLAs and uptime guarantees. Full breakdown in Does Xe have an API?.
Q11.Is the Xe API free?
No. Xe has no public free tier. Pricing is enterprise-only and typically starts around $799/month depending on volume and features. For free access, Frankfurter, ExchangeRate-API's free tier, or AllRatesToday's free plan are the common alternatives.
Q12.Is the Google Currency Converter API free?
There is no official public Google Currency API (the old Google Finance API was retired in 2012). What exists:
- The
GOOGLEFINANCEfunction in Google Sheets — free, ~20-minute delay, not a REST API. - Unofficial wrappers (e.g.
currency-api.appspot.com) — community-hosted, no SLA, can disappear without warning.
Don't depend on Google for production currency rates. Use a supported provider.
Q13.Is Fixer.io reliable?
Yes, within its bounds. Fixer.io is owned by apilayer and has been running since 2015. Paid plans have uptime guarantees and are generally reliable. Limitations on the free tier are heavy: 100 requests/month, HTTP only (no HTTPS), and EUR is the only allowed base currency. Most production users end up on Basic ($14.99/month) or Professional ($59.99/month). Our side-by-side comparison: AllRatesToday vs Fixer, Xe, ExchangeRate-API.
Q14.Is the MT5 API free?
No. MetaTrader 5 Manager and Gateway APIs require a licensed MT5 server and a paid integration agreement with MetaQuotes. Brokers may offer trial access to demo accounts. If you only need exchange rates (not trade execution), a plain currency API is dramatically simpler and cheaper.
Q15.How do you make a currency converter in Python with an API?
Minimal working example using Frankfurter (no key needed):
import requests
def convert(amount, src, dst):
r = requests.get("https://api.frankfurter.dev/v1/latest",
params={"from": src, "to": dst})
r.raise_for_status()
rate = r.json()["rates"][dst]
return amount * rate, rate
amount, rate = convert(100, "USD", "EUR")
print(f"100 USD = {amount:.2f} EUR (rate {rate})")Add error handling for timeouts and unknown currency codes, cache results for 30–60 minutes, and you have a production-ready converter. Deeper walk-through in How to get live exchange rates in Python.
Q16.What is the formula to calculate an exchange rate?
The exchange rate is the ratio of two currency amounts:
rate = target_amount / source_amountIf 100 USD buys 85 EUR, the USD→EUR rate is 85 / 100 = 0.85. To convert any amount, multiply by the rate:
250 USD × 0.85 = 212.50 EURThe inverse (EUR→USD) is 1 / 0.85 ≈ 1.176. Real-world rates include a spread — the "buy" and "sell" rates differ slightly, and that gap is the provider's margin. More: Mid-market vs retail exchange rates.
Q17.What is the GOOGLEFINANCE function for exchange rates?
In Google Sheets:
=GOOGLEFINANCE("CURRENCY:USDEUR")Replace USDEUR with any two concatenated ISO 4217 codes (GBPJPY, AUDCAD, etc.). For historical rates, add a date:
=GOOGLEFINANCE("CURRENCY:USDEUR", "price", DATE(2024,1,1))Rates are delayed ~20 minutes. Fine for spreadsheets; don't build production systems on it. For Excel, see How to get exchange rates in Excel.
Q18.Which is the best currency converter?
Depends on the use case:
- Sending money abroad: Wise — real mid-market rate, transparent fees.
- Quick lookup on web/mobile: Google search or XE.com.
- Embedding in software: AllRatesToday or Frankfurter.
- Enterprise / trading: Xe, OANDA, or Bloomberg.
For developers comparing providers head-to-head, see 10 best currency exchange APIs (2026).
Q19.What is the best currency converter app to use?
Most-recommended consumer apps in 2026:
- Wise — best mid-market rate + actual money transfer.
- XE Currency — clean UI, offline mode for travel.
- Revolut — multi-currency account with in-app conversion.
- Currency Converter Plus — simple free converter (ad-supported).
Q20.Where should you convert currency for the best exchange rate?
You get closest to the mid-market rate with online-first providers: Wise, Revolut, Currencies Direct, or OFX. Traditional banks and airport kiosks mark up the rate by 2–5% on top of a fee. Travel-friendly credit cards (no foreign transaction fee) are good for purchases abroad; avoid "Dynamic Currency Conversion" at the point of sale — always pay in the local currency.
Rule of thumb: check the mid-market rate first (Google, AllRatesToday, XE), then compare the rate you're offered. Any gap is the provider's margin.
Need a reliable currency API for your app?
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