DEV Community: Exchange Rate API

20 Currency & Exchange Rate API Questions Answered (2026) — Exchange Rate API

Exchange Rate API — Thu, 28 May 2026 08:46:18 +0000

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.

Is there a free API for currency conversion?
What is a currency API?
What is a forex API?
What is an FX API?
What is an open exchange rate?
Is the Frankfurter API free?
Is an exchange rate API free?
Is ExchangeRate-API free?
How much does ExchangeRate-API cost?
Does Xe have an API?
Is the Xe API free?
Is the Google Currency Converter API free?
Is Fixer.io reliable?
Is the MT5 API free?
Building a currency converter in Python?
What is the formula to calculate an exchange rate?
What is the GOOGLEFINANCE function?
Which is the best currency converter?
Best currency converter app?
Best rate when converting currency?

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.
Exchange Rate API -- 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://exchange-rateapi.com/api/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
Exchange Rate API	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 Exchange Rate API'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 GOOGLEFINANCE function 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: Exchange Rate API 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_amount

If 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 EUR

The 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: Exchange Rate API 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, Exchange Rate API, XE), then compare the rate you're offered. Any gap is the provider's margin.

Ready to integrate a reliable currency API? Get your free API key -- no credit card required.

Get started

npm install @exchangerateapi/sdk

10 Best Currency Exchange API Options for Developers (2026)

Exchange Rate API — Thu, 28 May 2026 08:45:50 +0000

If you are building a financial app, an e-commerce checkout, or an analytics dashboard, you need reliable exchange rate data. Hard-coding rates or scraping them from a website is slow, fragile, and a support nightmare. A currency exchange API solves this by delivering live, accurate FX data to your application on demand.

This guide explains what a currency conversion API is, how it works, which features actually matter, and compares the 10 best currency exchange APIs available to developers in 2026 -- starting with Exchange Rate API , which offers real-time rates from Reuters/Refinitiv, official SDKs, and a generous free tier with no credit card required.

What Is a Currency Conversion API?

A currency conversion API is a web service that returns live or historical exchange rate data over HTTPS in a machine-readable format -- usually JSON. Your application sends a request (e.g. "USD to EUR"), and the API responds with the current mid-market rate pulled from its data feeds.

Instead of maintaining your own pipeline of bank feeds, FX aggregators, and crypto exchanges, you integrate one REST endpoint and let the provider handle the data plumbing.

Why Developers Need a Currency API

Localized pricing -- display product prices in the visitor's local currency to reduce cart abandonment.
Multi-currency billing -- invoice SaaS customers in their own currency while reporting in a single base.
Financial reporting -- convert foreign transactions to the reporting currency at historical rates.
Trading and analytics -- feed dashboards, screeners, and backtests with live FX and crypto data.
Cross-border payouts -- calculate accurate settlement amounts for marketplaces and payroll systems.

How a Currency API Works

Your application sends an HTTPS request with a source currency, target currencies, and an API key.
The provider's server looks up the latest rates from aggregated data sources (banks, interbank feeds, exchanges).
The server returns a JSON response with the requested rates and a timestamp.
Your application caches or uses the rate to convert amounts.

Common Endpoint Types

Latest Rates -- the most recent exchange rates for one or many currency pairs.
Historical Rates -- rates on a specific past date, useful for accounting and charting.
Time Series -- a range of daily rates between two dates for trend analysis.
Convert -- a convenience endpoint that does the math for you.
Fluctuation -- the change, percentage change, and high/low over a period.

What Makes a Great Currency API

Accurate data sources -- interbank feeds, Reuters/Refinitiv, central banks, or top-tier aggregators.
Update frequency -- real-time tiers drop to 60 seconds or faster.
Coverage -- 150+ fiat currencies plus metals and crypto where relevant.
Transparent pricing -- a real free tier, no hidden fees, no credit-card walls.
Official SDKs -- so you don't write HTTP plumbing.
Clean JSON responses and strong documentation.
Security -- HTTPS, scoped API keys, reasonable rate limits.

The 10 Best Currency Exchange APIs in 2026

1. Exchange Rate API -- The Best Currency Exchange API for Developers

Exchange Rate API delivers real-time mid-market exchange rates for 160+ currencies , sourced from Reuters (Refinitiv) and interbank market feeds. It is purpose-built for developers: a clean REST API, official SDKs for JavaScript, Python, and PHP, and a free plan that does not ask for a credit card.

Highlights: 160+ currencies, 60-second updates, Reuters/Refinitiv sourcing, official SDKs, flat JSON responses, HTTPS-only, free tier with no credit card.

curl -X GET "https://api.exchange-rateapi.com/v1/rates?source=USD⌖=EUR" \
  -H "Authorization: Bearer era_live_your_api_key"

Best for -- fintech apps, SaaS billing, e-commerce localization, and any developer who wants real-time data without signup hoops.

2. CurrencyFreaks

Covers 1,000+ symbols including fiats, metals, and hundreds of cryptocurrencies. Update frequency ranges from 24 hours on the free plan down to 60 seconds on the Professional tier. A solid all-rounder if breadth of crypto coverage matters more than depth of FX sourcing.

3. Fixer

Delivers FX rates through a clean JSON API, with historical data going back to 1999 and sourcing aligned with the European Central Bank. The free plan is capped at 100 calls/month with hourly updates -- suitable mainly for prototypes.

4. ExchangeRate-API

Developer-friendly API with 161 currencies and a 1,500 request/month free tier. Paid plans bring hourly and 5-minute updates. Straightforward to integrate and well-documented.

5. Open Exchange Rates

A long-running provider with 200+ currencies and a large ecosystem of open-source client libraries. The free tier is hourly-updated and capped at 1,000 requests.

6. CurrencyLayer

Part of the APILayer network; 168 currencies and metals with a familiar endpoint structure. Free tier is limited to 100 calls/month.

7. XE

A well-known brand with 30+ years of FX history and 170+ currencies. Pricing is annual and geared toward enterprises rather than indie developers, with plans starting in the high hundreds per year.

8. CurrencyAPI

Straightforward REST API covering 170+ fiat currencies and cryptocurrencies, with sandbox access on paid tiers and 60-second updates at higher plans.

9. Alpha Vantage

Broader market-data API covering stocks, forex, crypto, ETFs, and commodities, plus 60+ technical indicators. Rate limits on the free tier are low but cross-asset coverage is unmatched in this list.

10. ExchangeRate.host

Simple, fast forex and crypto API with 19 years of historical data, 168+ symbols, and a free plan. Paid tiers unlock higher request limits and faster updates.

Comparison Table

API	Free Tier	Currencies	Update Frequency	Credit Card
Exchange Rate API	Free tier	160+	Real-time (60s)	No
CurrencyFreaks	1,000 req/month	1,000+	Daily (free)	No
Fixer	100 req/month	170+	Hourly	Yes
ExchangeRate-API	1,500 req/month	161	Daily	Yes (upgrades)
Open Exchange Rates	1,000 req/month	200+	Hourly	Yes
CurrencyLayer	100 req/month	168	Daily	Yes
XE	Free trial	170+	Up to 60s	Yes
CurrencyAPI	300 req/month	170+	Daily	Yes
Alpha Vantage	25 req/day	Multi-asset	Daily	No
ExchangeRate.host	Free plan	168+	Daily	No

How to Choose the Right API

Real-time trading or pricing -- pick a provider with 60-second updates (Exchange Rate API, CurrencyFreaks Pro, XE).
Accounting and reporting -- historical endpoints and audit-grade sources matter more than latency.
Crypto-first apps -- CurrencyFreaks or CurrencyAPI for breadth; Exchange Rate API if you need FX + metals.
Prototypes and hobby projects -- prefer free tiers without credit-card walls (Exchange Rate API, ExchangeRate.host).
Multi-asset dashboards -- Alpha Vantage is the clear choice for equities + FX + crypto in one API.

Getting Started with Exchange Rate API

Register at exchange-rateapi.com/register -- no credit card required.
Copy your API key from the dashboard.
Install an SDK or use curl:

npm install @exchangerateapi/sdk

import ExchangeRateAPI from '@exchangerateapi/sdk';

const client = new ExchangeRateAPI('era_live_your_api_key');
const rate = await client.getRate('USD', 'EUR');
console.log(1 USD = ${rate} EUR);

That is it -- you have live FX data in your application, sourced from the same feeds Bloomberg and Google Finance use.

FAQs

How do I start with a free currency API?

Sign up for the provider's free plan, get an API key, and send a request to the latest-rates endpoint using curl or your language's HTTP client.

Which languages can I use?

Any language that can make an HTTPS request. Exchange Rate API ships official SDKs for JavaScript/TypeScript, Python, and PHP.

Can I get both real-time and historical rates?

Yes -- quality APIs expose both. Historical endpoints usually accept a YYYY-MM-DD date parameter.

Do free tiers support cryptocurrency?

Some do (CurrencyFreaks, CurrencyAPI). Always check the documentation for supported symbols before committing.

How often are rates updated?

Free tiers typically refresh daily or hourly. Paid tiers drop to 60 seconds or faster. Exchange Rate API updates every 60 seconds.