If you are working with international clients, you need to have up-to-date information on currencies. However, the exchange rates are rapidly changing every day. Hence, it can be very difficult to get the correct value. By using a currency converter API, you can effortlessly get real-time currency rates. Also, it is very easy to implement into your web apps. You just need to write a few lines of code. In this way, the API can help you save time and money on unnecessary efforts. Also, it makes your business more efficient. There are lots of solutions available online. But which is the best free currency converter API? In this post, you will find the top currency converter APIs for 2025. Let’s dive in.
Table of Contents
What is a free currency converter API?
A free currency converter API is a tool that helps you easily integrate currency data into your applications. It offers web services for conversion. As a result, the developers can effortlessly convert one currency to another. The tool is free. Therefore, you don’t have to spend any money to use it.
How can I use a currency API?
To use an API in your application, you will need an API key. The key is unique. It will never be the same for all users.
Next, you have to insert the key into your code to implement the API. If you face issues, make sure to check the documentation. It usually covers all errors. Also, it provides useful information about different features.
What are the characteristics of the best free currency conversion API?
Super-Fast
Free currency converter APIs are built with speed and efficiency in mind. They can handle thousands of requests per second without any delay, ensuring smooth performance even during peak traffic times. The optimized infrastructure allows responses to be delivered in just milliseconds, making them highly suitable for applications that rely on real-time financial data, such as trading platforms, e-commerce stores, or fintech apps.
Reliable JSON API
These APIs provide a robust and scalable architecture with guaranteed uptime. Designed to support businesses of all sizes, they maintain consistent availability and can easily handle growing traffic volumes as your user base expands. With continuous monitoring and technical support in place, you can count on uninterrupted service, quick issue resolution, and seamless integration with your systems.
Trusted Sources
Currency data is aggregated from highly reputable financial institutions, including central banks and leading global data providers. This ensures that the exchange rates are not only accurate but also frequently updated to reflect market changes in real time. As a result, you can confidently rely on the rates for business transactions, analytics, and reporting.
Currency Conversion Endpoints
Currency converter APIs often provide flexible endpoints tailored for different use cases. For instance, single currency conversion endpoints make it easy to quickly convert one currency into another with minimal effort. In addition, many APIs also support batch conversions, time-series data, and historical rates, giving developers greater control and versatility when building applications.
Comprehensive Documentation
To help developers integrate quickly, these APIs come with detailed documentation that covers every aspect of the setup process. From authentication to advanced queries, everything is explained clearly, with code examples in multiple programming languages. This makes it easier for developers of all experience levels to implement the API into web apps, mobile apps, or backend systems without hassle.
Multiple Endpoints
The API features multiple endpoints. Each of them serves a different use case.
What are the 7 best free currency converter APIs in 2025?
1. Fixer – The Best Free Currency Converter API for 2025
Fixer is a lightweight and powerful API. It offers both current and historical forex (foreign exchange) rates. It comes with a straightforward API structure. As a result, you can implement it into your website in less than 10 minutes.
Fixer uses multiple sources for stable and reliable rates. It collects information from over 15 financial data providers and banks, including the European Central Bank. It updates the data every 60 seconds.
Fixer offers a bunch of API endpoints for the latest rates, historical rates, time-series data, fluctuation data, and conversion. It lets you easily retrieve the latest exchange rates for hundreds of currencies. You just need to write a few lines of code.
Here is an example of using Fixer to convert currencies in JavaScript programming language:
// set endpoint and your API key
endpoint = 'convert';
access_key = 'API_KEY';
// define from currency, to currency, and amount
from = 'EUR';
to = 'GBP';
amount = '10';
// execute the conversion using the "convert" endpoint:
$.ajax({
url: 'https://data.fixer.io/api/' + endpoint + '?access_key=' + access_key +'&from=' + from + '&to=' + to + '&amount=' + amount,
dataType: 'jsonp',
success: function(json) {
// access the conversion result in json.result
alert(json.result);
}
});You can use Fixer without spending any money through the free plan. Also, it offers a variety of paid plans.
Features:
- Offer bank-grade security
- Provides tech support
- Offers comprehensive documentation
- Supports SSL encryption
- Provides highly accurate current and historical currency values
- Supports portable JSON format
- Provides endpoint for easy currency conversion
2. Exchangerates API – A Top-Notch Free Currency Converter API
Exchange Rates API offers free service to developers. It supports both foreign exchange rates and crypto exchange rates. It collects exchange rate data from multiple central banks and commercial sources. Hence, you will always get accurate rates.
The foreign exchange rate API offers 170 forex currencies and 6000+ cryptocurrencies. Also, it provides 20 years of historical data. Besides, the average uptime is 99.99%. Overall, it’s a highly reliable API.
var requestURL = 'https://api.exchangerate.host/latest';
var request = new XMLHttpRequest();
request.open('GET', requestURL);
request.responseType = 'json';
request.send();
request.onload = function() {
var response = request.response;
console.log(response);
} 3. Open Exchange Rates – A Lightweight Free Currency Converter API
Open Exchange Rates is a lightweight JSON API. It provides accurate currency rates by utilizing reliable data sources. It provides both current and historical end-of-day rates. Also, the API is very easy to integrate into applications. Overall, it’s one of the best free currency converter APIs on the market.
Features:
- Supports open-source integrations and JSON format
- Provide live rate updates
- Offers current and historical currency values
4. Currencylayer – An Amazing Free Currency Converter API
Currencylayer is a free forex rate JSON API. It is compatible with different programming languages, including PHP, JavaScript, and Java. It enables you to easily request exchange rates for a specific timeframe. Also, you can get information on currency fluctuation.
Currencylayer supports over 168 currencies. It collects data from various commercial sources and banks. Depending on the plan, it can refresh data every 60 minutes, 20 minutes, or 60 seconds.
Features:
- Provides usage statistics and interactive documentation
- Supports 246-bit HTTPS
- Offers current and historical currency values
- Supports portable JSON format
- Offers currency conversion endpoint
- Supports timeframe and currency-change queries
5. XE – A Great Free Currency Converter API
XE’s currency data API has been serving developers for years. You can easily implement it in different applications. like Microsoft Dynamics, Sage, and SAP. The API allows you to effortlessly make timeframe queries. Also, it provides extensive documentation. It explains all the features in detail.
The API supports 170+ currencies. It gathers data from 100+ global sources. It is a free currency converter API. Hence, you can use it without spending a penny. However, if you want to use advanced features, you have to go for the premium plan.
Features:
- Provides current and historical data from 1998
- Offers data on currency volatility
- Supports customizable margin rates
6. Currency API – Another Great Free Currency Converter API
Currency API offers current and historical foreign exchange rates. It supports over 170 currencies. Also, it supports cryptocurrency conversion.
The tool uses JSON REST API to provide real-time foreign exchange rates. It updates the data every 60 seconds. As a result, you will always get accurate rates. The API comes with a robust infrastructure to handle millions of requests every day. It is highly reliable.
Currency API offers a free API key. It gives you 300 free credits per month.
7. IBAN– Forex Reference Suite
IBAN’s Forex Reference Suite is one of the top currency conversion APIs for 2025. It provides data from central banks and trusted sources. Therefore, you will never have to worry about data reliability.
The API updates the currency rate every 10 minutes. It gives you access to more than 154 currencies. It provides you with up-to-date conversions that reflect the fluctuations in the market.
Is Fixer really the best free currency conversion API for 2025?
Fixer.io provides real-time exchange rates for 170 world currencies. It updates the data every 60 seconds. Hence, you will always get the latest rates. The API collects data from authority sources. Also, it encrypts the connection with bank-grade 256-bit SSL encryption. As a result, hackers will face a very hard time intruding into the system. On top of that, it is very easy to implement into web applications. For these reasons, Fixer.io is considered the best free currency conversion API for 2025.
FAQs
1. How do I get started with a free currency converter API?
To get started, you need to sign up for an API provider like Fixer, Exchangeratesapi, or Currencylayer. Once registered, you’ll receive a unique API key to authenticate requests. Simply add it to your code and start retrieving exchange rates.
2. What programming languages can I use with a currency API?
Currency converter APIs provide responses in JSON, which is supported by most programming languages, including JavaScript, Python, PHP, and Java.
3. Can I get both real-time and historical exchange rates using these APIs?
Yes. For example, Fixer provides real-time exchange rates updated every 60 seconds, along with historical forex data for different dates. This is especially useful for financial analysis and reporting applications.
4. Do free currency APIs also support cryptocurrency exchange rates?
Some APIs support both traditional currencies and cryptocurrencies. For instance, Exchangeratesapi provides data for forex currencies as well as crypto exchange rates, making it a great option for hybrid apps.
5. What is the average update frequency of currency APIs?
Update frequency depends on the provider. Fixer updates every 60 seconds, while Currencylayer refreshes data at different intervals depending on your plan (60 minutes, 20 minutes, or 60 seconds).
