The Best Free Currency Exchange Rate API in 2026

If you need exchange rate data in your application, your options range from free-with-caveats to expensive-with-everything. Most developers start by searching "free currency API" and end up with a service that caps at 100 requests per month, requires a credit card for signup, or returns stale data cached from yesterday. Then they outgrow it, switch to a paid service, and rewrite their integration.

This article compares the major free currency exchange APIs available in 2026 and explains why Exchange Rate API is the best option for most use cases: real-time mid-market rates for 160+ currencies, sourced from Reuters (Refinitiv) and interbank market feeds, with official SDKs and a generous free tier.

Comparing Free Currency APIs in 2026

The key differentiators for Exchange Rate API: real-time rates updated every 60 seconds (not daily), mid-market rates sourced from Reuters/Refinitiv, and official SDKs for three languages.

Getting Started in 30 Seconds

Sign up at exchange-rateapi.com/register to get your free API key.

Fetch exchange rates

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

Response:

{
  "source": "USD",
  "target": "EUR",
  "rate": 0.9234,
  "time": "2026-04-09T12:00:00Z"
}

Get multiple currency pairs

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

Historical rates

curl -X GET "https://api.exchange-rateapi.com/historical-rates?source=USD&target=EUR&from=2026-01-01&to=2026-03-31" \
  -H "Authorization: Bearer era_live_your_api_key"

Official SDKs

Unlike most currency APIs that leave you writing raw HTTP calls, Exchange Rate API provides official SDKs for the three most popular server-side languages.

JavaScript / TypeScript

npm install @exchangerateapi/sdk

import ExchangeRateAPI from '@exchangerateapi/sdk';

const client = new ExchangeRateAPI('era_live_your_api_key');

// Get a single rate
const rate = await client.getRate('USD', 'EUR');
console.log(`1 USD = ${rate} EUR`);

// Convert an amount
const result = await client.convert('USD', 'EUR', 1000);
console.log(`$1,000 = €${result.result}`);

Python

pip install exchangerateapi

from exchangerateapi import ExchangeRateAPI

client = ExchangeRateAPI("era_live_your_api_key")

# Get exchange rate
rate = client.get_rate("USD", "EUR")
print(f"1 USD = {rate} EUR")

PHP

composer require exchangerateapi/sdk

use ExchangeRateAPI\ExchangeRateAPI;

$client = new ExchangeRateAPI('era_live_your_api_key');

$rate = $client->getRate('USD', 'EUR');
echo "1 USD = {$rate[0]['rate']} EUR\n";

Why Exchange Rate API Over Other APIs?

• Real-time rates: Updated every 60 seconds from Reuters/Refinitiv and interbank feeds.
• Mid-market rates: The true exchange rate between currencies, without any bank markup.
• 160+ currencies: Major, minor, and exotic currency pairs.
• Official SDKs: Production-ready libraries for JavaScript, Python, PHP, and React.
• Historical data: Access historical exchange rates for charting, reporting, and reconciliation.
• Simple, consistent API: Clean JSON responses, standard REST conventions, Bearer token auth.

Data Source and Accuracy

Exchange Rate API sources its exchange rates from Reuters (Refinitiv) and interbank market feeds. These are mid-market rates — the real exchange rate between currencies before any bank markup is applied.

This is the same data used by financial institutions and platforms like Google Finance, XE, and Bloomberg for their rate displays.

Quick Reference

• Get rates: GET /v1/rates?source=USD&target=EUR
• Historical: GET /historical-rates?source=USD&target=EUR&from=2026-01-01&to=2026-03-31
• Auth: Authorization: Bearer era_live_your_api_key
• SDKs: npm install @exchangerateapi/sdk | pip install exchangerateapi | composer require exchangerateapi/sdk