Currency conversion is crucial for developers working on e-commerce platforms, financial applications, travel booking systems, and more. Developers often need real time exchange rates for seamless cross-border transactions or pricing updates. Fortunately, various currency converter APIs offer free tiers, but not all free options are equal. In this article, we'll compare the top free currency converter APIs, highlighting their pros, cons, and limitations to help you make an informed decision.

1. ExchangeRatesAPI (by APILayer)

Free Plan Limits:

• API Calls: 250 requests/month
• Currencies Supported: 170+
• Data Frequency: Hourly updates

Pros:

• Extensive Currency Support: ExchangeRatesAPI supports over 170 currencies, including major and exotic ones, making it a versatile option for developers working in diverse regions.
• Comprehensive Documentation: The API offers detailed documentation that simplifies the integration process, even for beginners.
• Multiple Endpoints: Developers can access not just currency conversion but also historical rates, time-series data, and fluctuation metrics.
• Integration with APILayer: As part of the APILayer ecosystem, it integrates well with other APIs like IP geolocation or VAT calculation, making it a strong choice for developers working across multiple data sets.

Cons:

• Request Limitations: The free plan's 250 monthly requests may be insufficient for applications requiring frequent updates or high traffic.
• Hourly Updates: The hourly update frequency may not be suitable for trading or applications needing more frequent updates.
• Paid Tier Required for Advanced Features: If you need minute-level data or unlimited API calls, you'll need to upgrade to a paid plan.

Best For: Developers needing reliable, real-time conversion rates for lightweight applications or projects in early development stages.

2. Open Exchange Rates

Free Plan Limits:

• API Calls: 1,000 requests/month
• Currencies Supported: 170+
• Data Frequency: Hourly updates

Pros:

• Generous Free Plan: With 1,000 requests per month, Open Exchange Rates provides more flexibility than some other options for developers working on small- to medium-sized projects.
• Extensive Currency Support: Like ExchangeRatesAPI, Open Exchange Rates offers over 170 currencies.
• Detailed Documentation: The API comes with excellent documentation, making it easy for developers to get started and integrate with different platforms.

Cons:

• Limited Data: Only the latest exchange rates are available in the free tier. If you need historical data or time-series features, you'll need to upgrade.
• No Fluctuation Metrics in Free Plan: Unlike some competitors, the free tier does not provide access to advanced metrics like rate fluctuations or conversions against commodities.

Best For: Developers who need a slightly higher request limit and basic exchange rate data without the need for advanced features.

3. CurrencyLayer

Free Plan Limits:

• API Calls: 250 requests/month
• Currencies Supported: 168+
• Data Frequency: Hourly updates

Pros:

• Wide Currency Support: CurrencyLayer offers access to 168 currencies, covering a significant portion of global markets.
• Simple Integration: Its user-friendly documentation and lightweight JSON responses ensure a smooth integration process.
• Reliable Data: CurrencyLayer uses exchange rate data from reliable financial sources, making it a trustworthy choice for developers.

Cons:

• Limited API Calls: Like ExchangeRatesAPI, the free plan's 250 monthly requests may not suffice for high-demand applications.
• No Historical Data: The free plan doesn’t allow access to historical exchange rates, limiting its usefulness for in-depth financial analysis.
• Updates Only Hourly: Applications requiring more frequent data updates, such as trading platforms, will need to upgrade to a paid plan.

Best For: Developers needing an easy-to-use currency API for projects that don't require heavy usage or advanced data features.

4. Fixer.io

Free Plan Limits:

• API Calls: 100 requests/month
• Currencies Supported: 170+
• Data Frequency: Hourly updates

Pros:

• Comprehensive Currency Coverage: Fixer.io supports over 170 currencies, making it suitable for both regional and international applications.
• Historical Rates: While limited to the paid plan, Fixer.io's historical data feature can be an attractive option for developers needing retrospective financial information.
• API Integration Simplicity: The API offers clean, well-documented endpoints for easy integration into various systems.

Cons:

• Lowest Free Plan Limits: With only 100 API requests per month, Fixer.io’s free plan is the most restrictive. Developers with higher needs will have to look elsewhere or upgrade to a paid tier.
• No Free Access to Historical Data: Historical exchange rates, fluctuation data, and other premium features are locked behind a paywall.

Best For: Developers working on projects with minimal data needs or who are simply experimenting with API integration.

5. FreeForexAPI

Free Plan Limits:

• API Calls: Unlimited
• Currencies Supported: 19
• Data Frequency: Real-time updates

Pros:

• Unlimited API Requests: FreeForexAPI stands out by offering unlimited requests in its free tier, making it perfect for high-traffic applications.
• Real-Time Updates: For developers needing up-to-the-minute currency data, FreeForexAPI is a fantastic choice.
• No Need for Registration: The API is accessible without needing to sign up or register, making it extremely convenient for quick projects or testing purposes.

Cons:

• Limited Currency Support: With only 19 supported currencies, FreeForexAPI falls short for developers needing broader international coverage.
• Fewer Features: The API focuses on real-time rates but lacks the more advanced features—such as historical data or time-series information—offered by its competitors.

Best For: Developers building applications that require high-frequency real-time data and are focused on major global currencies.

Conclusion

Choosing the best currency converter API free depends on your specific project requirements. If your app is low-traffic or in the development phase, ExchangeRatesAPI or CurrencyLayer offer solid options with reasonable free tier limits. Open Exchange Rates gives a bit more flexibility with 1,000 free monthly requests, making it better suited for medium-sized projects. For more frequent real-time updates, FreeForexAPI stands out, although its limited currency support might not suit everyone. Finally, Fixer.io offers a strong foundation for lightweight apps but comes with the tightest restrictions in its free tier.

Carefully evaluate your app's traffic, frequency of updates, and the need for historical data when selecting the right API. For scaling beyond basic usage, be ready to upgrade to paid plans, as free tiers typically have significant limitations.

Ultimately, the best free currency converter API is the one that aligns with your project's specific needs without compromising on essential features or scalability.