Last updated
August 7, 2023

The best exchange rates APIs of 2021

Emma Jagger

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The current fintech boom is seeing numerous financial apps and services appear worldwide.

Whether you’re looking to build a great trading app, or are just interested in watching global exchange rates, we have decided to review several APIs that give you access, as a developer, to the most critical information about current exchange rates. 

Let’s look at what makes these API good options for your next project, and how you can use an Exchange Rate API. 

What Is an Exchange Rate API?

Exchange Rate API are databases that track and use data from major international banks to create an up to date track record of the current value of different currencies. The API themselves are short snippets of code that can be inserted into an app or webpage to provide access to an Exchange Rate tracker. 

These API are widely varied, with some offering tracking that include precious metals and even cryptocurrencies like Bitcoin. Other API can also track things like stock market prices. 

Many of the best of these API also offers historical data about foreign currencies and the exchange rates that have predominated for the last several years. That historical data can help provide context when you're making market decisions or planning out a budget for an international trip.

Great exchange rate API will offer several features, which are usually a combination of: 

  • Coverage of all or most major global currencies
  • Coverage of more minor currency types
  • Real-time updates OR interval-based updates
  • May offer coverage of cryptocurrencies
  • May offer coverage of stock markets
  • May cover options and other important financial indicators 

These tools are fantastic for making informed market decisions if you're working in the exchange market. But they are also a great tool for travelers and many other people. Don’t think that these tools are only accessible or useful for people working the financial markets. 

Our IP geolocation API may also be a good addition to many exchange rate API, letting users tap into the most relevant markets based on their location (if you program the feature that way, of course).

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How To Use an Exchange Rate API:

The basic implementation of your API is fairly similar, no matter which API you’re using. The first thing you need is an API key, which is usually specific to the API you’re using, although some services do offer API keys so you can try an API before subscribing. 

Once you have the key you insert it into your existing code to implement the API. You may need some troubleshooting before it starts working perfectly, but most API will also come with some additional documentation and tools you can use to help get the features functioning within your app or website. 

Of course, you may also need to tweak your subscription or the features you use after implementing a new API since it can be difficult to predict how you’re going to use any API before your app is up and running. 

Since exchange rate API are dealing with relatively sensitive information, it’s also a good idea to use phone validation and email verification API to add an extra layer of security. Those security measures can add real peace of mind for your project’s eventual users, and can help prevent the wrong people from accessing a project you’ve built for yourself. 

What are the 6 Best Exchange Rate API?

Here are 6 of the best exchange rate API. We’ll also provide a more in-depth review in a moment, so don't worry. But if you're in a hurry or would prefer to pick an API based on your own research, these should all be on your shortlist.  

  1. OANDA
  2. Open Exchange Rates
  3. Xignite
  4. Currencylayer
  5. Exchange Rate API
  6. Fixer


OANDA is a relatively premium API that’s certainly best for developers who are looking to create or add features to a high-traffic website or app. It can also be a useful tool if you’re looking to develop a program for internal use within a company. 

The API currently has data tracking over 200 different currencies and offers tracking of several of the more valuable precious metals. That collection of data gives you an incredible window into what the currency market is doing and means that you have volumes of data available if you’re trying to plan or budget for an international vacation. 

OANDA also has one of the most extensive collections of historical exchange rate data, going back to 1990 for the currencies covered by the API. OANDA also occasionally adds new currencies when needed, based on the impact of a currency or how common that currency has become on the global market. 

However, OANDA is also one of the most expensive API you can get, making it best for large developers and less small-developer friendly. They offer the API for free for 30 days but plans accessing OANDA start at $400 after that initial trial period.

They do occasionally run additional free months after sign up though, so you might be able to get a deal if you subscribe while they are running a special.


  • Extensive coverage of over 200 currencies
  • Provides historical data going back to 1990
  • Spot rates updated every 5 seconds
  • Also provides forward rates 
  • Data from 39 central banks globally


  • Relatively expensive

2. Open Exchange Rates

If you’re looking for a slightly more affordable API that still offers an extensive library of currencies, and also offers real-time exchange rate updates, Open Exchange Rates might be a good choice of API. 

This API covers all of the base currencies globally. They also have several features that can make working the exchange market much easier, including bid-ask and midpoint prices. You can also pull intraday price histories, depending on your subscription level. 

That’s where this API starts to be different for different users. Open Exchange Rates does offer a free version of their API. This more limited version uses USD as their base currency and provides up to 1,000 calls per month. Exchange rates on the free version update every hour. 

The Developer Plan, which is their lowest-paid offering, starts at $12 a month, while their Unlimited Plan costs $97 a month. The Unlimited plan also offers updated rates every 5 minutes, letting you stay on top of current Exchange Rates to make more informed choices. 

Paying on an annual basis, instead of a monthly payment, also offers 2 free months with your subscription, which is a great way to keep costs down if you need to invest in one of their costlier plans. 


  • Can match the cost to your needs
  • Free version is powerful enough for many users
  • Wide currency library including all global base currencies
  • Discounts offered for annual subscriptions


  • No option for real-time updating
  • Free version limits users to USD base currency

3. Xignite

Xignite is one of the big names in exchange rate API, partially because they have 12 years of experience behind them, and partially because they also have a history of successful clients who have used their API in order to create incredibly effective and powerful software. 

Xignite is also one of the most accessible and flexible API, giving you the option of several different coding styles as well as different ways to receive the data provided within the API. In addition to the flexibility of their data, you can also expect Xignite to be one of the most reliable and consistent options because they source their data from over 250 different exchange data providers. 

The API is also highly scalable, so you can work with them at many different sizes, adding features and options as your business grows and gains a wider customer base. 

However, while Xignite offers a free 7-day trial on their services, they don’t publish pricing or feature packages. If you want to use their API, you need to contact them directly to get a quote for the services you want and need. 

Unfortunately, that also means that we don’t know how many calls are allowed in a month or other important details. So, if you’re considering this API, it’s important to consult with them to see if their services are a good match for your needs before you sign up for a key. 


  • A large number of data providers ensures accuracy
  • Lots of experience working with successful customers to meet their needs
  • Provide a large amount of historical data on currency pricing
  • Free trial offered to help you try the services before you commit 


  • Pricing and package detail not published
  • Flexibility of design also means that you may need to consult with them more often to get your API services set up and working well. 

4. Currencylayer

Currencylayer is another highly flexible option that gives you a wide range of different subscription levels to choose from. It’s also one the exchange rate API that also offers a free version, although that version is fairly limited. 

The free API provides up to 250 requests a month, with daily rate updates and historical rates data that can make predicting the market and making good market decisions much easier. They also offer some limited technical support for users of the free version, which is relatively rare in free API.

The next level up starts at $9.99 a month, with a slight discount if you sign up for an annual plan instead of a monthly subscription.

The historical data provided by Currencylayer goes back to 1999. This API also allows you to convert currency directly in the API, using real-time or historical rates. It also has the power required to support Time-Frame Queries and Currency-Exchange Queries, which make your job (and your customers’ jobs) much easier. 

Currencylayer can also be relatively flexible within the constraints of your subscription. Since each subscription level has a maximum number of API calls supported in a single month, they provide warnings as you approach your call limit. Depending on demand, Currencylayer may also be able to support overages of up to 20% of your call limit, though that isn’t a guarantee. 


  • Relatively powerful free version
  • Added flexibility within your subscription 
  • Extensive library of historical data
  • Highly Affordable
  • Trusted b many highly successful businesses


  • All subscriptions levels have limited API calls
  • Different subscriptions offer different refresh times

5. Exchange Rate API

Exchange Rate API provides good documentation for how to install and begin using the API. They also offer technical support (with effective reps) for all paid plans. Unfortunately, while Exchange Rate API does offer a free version of their API, they don’t provide customer support for that version. 

That said, Exchange Rate API is another reasonably affordable option, with plans starting at $9 a month. They also accept all major payment options, as well as PayPal, which makes them a very flexible option for startup companies and at-home developers, and well as major corporations. 

Unlike most other top exchange rate API, Exchange Rate API (fantastic name, isn’t it?), doesn’t offer an annual subscription. However, that also works to make it easier for you to cancel if you ever decide that you need a different subscription level, or a different API altogether. 

However, another downside of this API is that their subscriptions only offer a 60-minute refresh rate on their data, which can limit your options if you’re trying to make quick trades and monitor variations in the market more closely. 

  • Easy to install and start using
  • Offers a fairly comprehensive library of currencies 
  • Offers historical data
  • Has a free version suitable as a trial offer, or for small developers
  • Highly affordable plans


  • The fastest refresh rate is 60 minutes
  • The free version does not offer any customer support

6. Fixer

Fixer is one of the most popular and most well-trusted API out there, with the backing of a fairly comprehensive set of pre-designed plans, as well as custom pricing on larger orders that could not be otherwise covered by the other plans on offer. 

They draw their data from 16 different sources, which is reasonably reliable considering the high quality of those sources. 

The free version of this API offers 1,000 API calls per month and provides historical exchange rate data, as well as an hourly refresh rate that is reasonably advanced for a free API.

Their basic plan starts at $10 a month, offering premium support, the same hourly refresh rate, and coverage of all base currencies. From there, higher subscription tiers include different types of conversion endpoints, higher tier troubleshooting support, and faster updates, with a top speed 60-second refresh rate. 

The 170-currency coverage is only slightly smaller than some of the more expensive premium API, and more than enough for your average trader to use quite effectively. 

Fixer also has the advantage of being a particularly fast option, with an average response time of only 48 milliseconds.


  • 170 currencies tracked
  • Incredibly quick response time
  • 19 years of historical data
  • Offers volume discounts for the largest subscribers


  • Free subscriptions only offer limited support

What To Look For In An Exchange Rate API?

While these are certainly some of the best Exchange Rate API out there, they certainly aren’t the only ones, and it may not be immediately obvious why these are some of the best choices. Here are some of the criteria you should look for in a good exchange rate API to make sure you’re making the most out of your subscription and can offer competitive benefits and services to your customers. 

How Many Currencies, and What Type, Are Provided?

This is one of the most important aspects of a good Exchange Rate API. While there are some good options out there that only offer a few dozen currencies, more currency data is generally better. 

The very best options hover around 200 different global currencies, including precious metals or cryptocurrencies. Anything above 150 is very good, while some of the most limited will offer as little as 30-50. 

You should also pay attention to how many currency combinations are offered by the API since some exchanges might be limited. Here too, more is better.

Beyond just how many currencies are provided, it’s also important that major currencies are included in their offerings. An API with a large roster of currencies, but which doesn’t offer USD, Euros, or Pound Sterling wouldn’t be particularly useful, for instance. 

By the same token, a smaller list of currencies might still be valuable and useful, if most of all of the major global currencies are included in that list. 

What Kinds of Data Sources Does the API Use?

Exchange rate APIs are all about Data and the source of that Data matters. There are two things you should look for when you're looking at the data provided by your chosen API, how many sources do they draw from, and how trustworthy is each individual source?

You should look for more than 10 sources for a good data set. That’s because different sources update at different rates, so aggregating the information provided by each allows the exchange rate API to accurately track and measure global trends in order to provide the most accurate possible value on each of their included currencies. 

Look for big banks, and sources like the Federal Reserve when you’re looking at which sources each API use. While some API will also draw on smaller banks and databanks (which is fine, so long as those sources don’t overwhelm their listing), you should also see the bigger and more trustworthy banks and institutions represented. 

Some API offer dozens of data sources. That's a nice perk since you know that they are likely to have the most accurate results, but it isn't strictly necessary. More than 10 is fine, beyond that, so long as they are using reliable sources for their data, additional sourcing isn’t likely to change rates or refresh intervals significantly. 

How Often Does the API Update?

Another hugely important aspect of any exchange rate API is how often that API can update, and how many calls you can place within a month. If your API has limited call rates, it's also important to know whether that call rate is a backwards rolling figure for the last 30 days, or if it's a calendar month plan, since that can affect how you use the API.

The best exchange rate API will be able to give you current exchange rates within a margin of only a few seconds, though this kind of near-real-time support is relatively rare from this type of API. More common are refresh intervals between 10-60 seconds, every 5 minutes, every hour, or every day. 

Ultimately, which kind of updating you need depends entirely on how you use the API. If you’re looking to make money on the currency exchange market, it’s important to have a faster refresh interval so that you can take advantage of rapid fluctuations in rates. 

However, some users, even market workers, may need less detailed information if they’re using these API for long-term exchanges. 

Think carefully about how often you need these updates before you pick your subscription level with any API provider. Most exchange rate API tie refresh rate to the subscription level, so you may need a higher level subscription if you need a faster refresh rate, even if you don’t need the other features that come with that subscription. 

Where Do I Get My API Key?

Usually, the best place to get your API key is from the developer themselves. They’ll provide a key (which should be inserted into the API code) when you pick your subscription level. 

For API that offer a free version, usually, all you have to do is select the free subscription level and they will provide a key. 

Some services will offer an API key that gives you a trial run through a third party instead of directly through the developer.

If you need to change your subscription level, you’ll also likely need to change the API key you’re using to reflect the new permissions associated with your account. 


Exchange rate API are incredibly useful and flexible tools that give you a lot of information and can be hugely empowering if you’re looking to provide currency information, as well as market histories. 

Of course, they’re far from the only API out there, with options for Geolocation and even Weather, you can probably find the right combination of API for almost any app. 

You may also want to consider our VAT validation API to help protect your user’s security by validating that any international sales or transactions are fully legal as they happen.

Remember to look carefully at the refresh rate and call limits before you subscribe to any new API, and to look at the quality of data sources. But regardless of your needs, there is probably an API out there for you. 

We've intentionally chosen from API designed for at-home developers all the way through to API that cater to large corporations and enterprise-level groups. But our recommendations for how to choose the best exchange rate API will serve you well even if you decide to do your own research and look for API that aren’t included in our list. 

Emma Jagger
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