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Building a Real-Time Currency Converter in Java Using Currencylayer API

a person holding dollar bills

In the world of global finance, real-time currency conversion plays an important role in many fields, from trading to investing. Access to accurate and up-to-date currency data is of vital importance, especially in the process of developing financial applications. This data allows users to make reliable financial decisions. At this point, many currency conversion services have emerged today to help businesses and developers. These services have recently formed the basis of the real-time currency converter in Java applications.

The technological revolution in currency conversion has essentially reduced transactions that took hours to mere milliseconds. Real-time currency conversion applications, especially developed with Java, the most used programming language of recent times, allow users to convert between hundreds of currencies within milliseconds. The most popular currency conversion API preferred by developers in these applications is currencylayer. In this article, we will introduce the currencylayer API, which has a large currency pool that supports hundreds of currencies. Then, we will develop a real-time currency converter in Java with this exchange rate API.

Understanding Currencylayer API

home page of the currencylayer api

Currencylayer API is a powerful platform that provides access to real-time exchange rate data. This API is a highly performant and comprehensive currency converter API that works at high speed. In this respect, currencylayer API is the number one choice of 250,000 developers and businesses, especially global businesses such as Freelancer, TeamViewer, and Disney. Additionally, the currencylayer API also has simple and understandable documentation that allows users to retrieve exchange rate data quickly and easily. With these features, it offers developers and financial application owners a powerful solution for integrating exchange rate data.

Nowadays, with the globalizing economy and the increase in digital trade, providing instant access to exchange rate data has become important. Currency rates play a big role in the decisions users make when trading, investing, or especially when traveling. Therefore, financial apps and websites must provide access to up-to-date and accurate exchange rate data. Thus, businesses can use this data to improve user experience and financial decision-making processes. Currencylayer API has recently become an important tool to meet this need.

Currencylayer API always prioritizes reliability and accuracy. The API retrieves real-time data from trusted data providers and banks around the world and constantly updates it to keep it current. In addition, the high performance and stable service of currencylayer API enable users to trust the data.

Explore the role of accurate exchange rate API.

Key Features of Currencylayer API

Currencylayer API is one of the most reliable platforms in the market that provides access to exchange rate data by offering a variety of key features. This API provides users with access to historical exchange rate data and real-time rates. It supports historical currency data back to 1999 with its unique database. Thus, users can analyze past exchange rates and discover trends with historical exchange rate data. On the other hand, it also provides real-time data, allowing users to follow instant exchange rates. Additionally, this API also has a currency conversion endpoint. This endpoint is one of the currencylayer’s most used endpoints. With this service, it provides currency conversion for both live and historical data of the currencies it supports. These features mainly help businesses and investors make informed decisions when performing financial analysis or trading.

Reveal the differences between currencylayer and OpenExchangeRates APIs!

Currencylayer API has a currency converter API layer that is available for free. This layer only provides daily updates and historical rates services. Additionally, its free plan is limited to 100 API calls per month. However, compared to the free option, premium plans offer more features and extensive data access. For example, premium plans often provide faster update frequencies, larger data archives, and access to endpoints. Additionally, paid plans generally offer the right to make more API requests. Thus, developers can easily choose this API for larger-scale applications or more intensive use cases.

Finally, the ease of integration and the broad currency support of the currencylayer free currency converter API is one of its most important advantages. This API, which has a developer-friendly structure, is designed to be compatible with different platforms and all major programming languages. So developers can easily integrate the API into their existing projects. Additionally, the currencylayer API supports more than 168 currencies, making it ideal for applications with a global user base. This broad currency support enables users to convert between various currencies around the world, creating a significant advantage for businesses trading in different markets.

Real-Time Currency Conversion with Currencylayer in Java

Currencylayer easily integrates into today’s major programming languages. It also provides sample, easy-to-understand integration codes for many programming languages in its documentation. One of the most popular programming languages in which this API is used today is Java. In this part, we will integrate the currencylayer API into Java 21 and develop a real-time currency converter application.

Get an API Key

We need an API key to develop a currency converter application with the currencylayer API. This API offers us affordable and high-limit subscription plans. It also offers that currency conversion service only with its paid plan. Therefore, let’s sign up for a paid subscription plan and get an API key.


After obtaining the API key, we can now start developing our application. For this, we will use IntelliJ IDEA IDE in this application. Let’s create a Java 21 application with this IDE and select Maven as the build system option.

real-time currency converter in java

Then, let’s enter the Main class in the opened application and add the following codes.

With this application, we developed a currency converter in real time using the currencylayer API.


Before testing the application, let’s put our API key in the ‘YOUR_API_KEY’ field and run the application. After running the application, the response in the console of the application is as follows:

Best Practices for Using Currency Converter APIs in Java

When using currency converter APIs in Java applications, adopting some best practices is very important for the application development and maintenance phase. Focusing on issues such as effectively managing API calls, caching strategies, and error handling ensures efficient and reliable use of these APIs.

Java’s multithreading capabilities can be leveraged to manage API calls, such as opting for asynchronous calls and using the thread pool. Asynchronous calls allow the application to continue other operations while waiting for API calls to complete. Additionally, the thread pool ensures that API calls are managed concurrently and that the application’s performance is maintained in overload situations.

Discover the multithreading in Java!

Caching strategies both increase speed and reduce API usage by preventing API calls from being repeated frequently. In Java, tools like ConcurrentHashMap can be used for caching operations. Additionally, distributed caching tools such as Redis cache may be preferred. To determine cache duration and avoid unnecessary calls, it is important to consider the update frequency and data exchange of the API.

Learn how to use Redis Cache with Java Spring Boot!

Error handling is another important consideration when using currency converter APIs such as currencylayer in Java applications. Appropriate error-handling strategies should be determined considering situations in which API calls may fail. Additionally, to optimize API usage, it’s important to stay within free tier limits or manage costs on premium tiers. Analytics tools can be used to monitor API usage and reduce unnecessary calls. It’s also important to choose an API plan that suits the application’s needs and budget.

Use Cases and Benefits

Real-time currency conversion forms the backbone of many real-world scenarios. Particularly in areas such as international trade, e-commerce, and financial transactions, having access to accurate and up-to-date exchange rate data is vital. For example, in transactions with a company’s international customers or suppliers, pricing or cost calculations can be difficult without accurate exchange rate data. Additionally, an accurate currency conversion service is important for travelers or foreign investors. Managing their budgets and making financial decisions by monitoring exchange rates is also associated with real-time exchange rate data.

The impact of accurate and up-to-date conversion data can be demonstrated through many testimonials or case studies. There are many examples where financial institutions, e-commerce platforms, and even international companies in particular have optimized their transactions by having access to accurate exchange rate data. For example, an e-commerce company can use real-time exchange rate data to increase its international sales. Similarly, with accurate exchange rate data, an investment firm can analyze portfolio performance and optimize risk management.

Pick up how currency API can supercharge your global reach!

Currencylayer API plays an important role in facilitating international transactions and global access. This API provides real-time exchange rate data on more than 168 currencies, making it easy for users to make transactions worldwide. Especially financial applications, e-commerce platforms, and international companies carry out their transactions based on the reliable and up-to-date data offered by the currencylayer API. By using the API, international transactions are accelerated, costs are reduced, and customer experience is directly improved.

The role of the currencylayer API is also strikingly important in reducing the complexity of global trade and financial transactions. The API enables transactions to occur more efficiently by automating conversions between different currencies and providing accurate data. This helps make international transactions more reliable. It also easily increases the competitive advantage of these businesses. As a result, the currencylayer API has become an indispensable tool in international trade and financial transactions.


As a result, integrating the currencylayer API into Java applications is an effective way to provide fast, reliable, and easy access to real-time exchange rate data. Thanks to this integration, international transactions become more efficient and reliable. Additionally, starting with currencylayer’s free tier, it is very important for beginning developers to try out and use the API. This allows developers to understand the functionality of the API and explore how to use it in their applications, free of charge. All in all, the currencylayer API is a powerful and accessible tool for anyone looking to integrate exchange rate data in their Java applications.

Try currencylayer API for free and start developing a real-time currency converter in Java application with it!


Q: Does currencylayer API provide a free API key for testing?

A: Yes, currencylayer API provides a free API key for users to test. It offers 100 API calls in its free plan.

Q: Why is a real-time currency converter in Java popular?

A: Real-time currency converter is popular in Java because Java is a programming language and platform preferred by a wide range of users.

Q: Is currencylayer a well-equipped currency exchange rates provider?

A: Yes, the currencylayer is a comprehensive provider of currency conversion rates. The API offers real-time exchange rate data on more than 168 currencies and also provides access to historical data.

Q: Does the currencylayer API work easily in a Java program?

A: Yes, it does. Currencylayer API works easily in Java programs. It even provides sample integration codes for Java in its documentation.

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