Currency Exchange API: It’s Not as Difficult as You Think

Updated

Currency Exchange API converts and exchanges currencies efficiently and effortlessly. There are many Currency Exchange APIs in the market today. However, choosing the ideal one that will get the best out of your application is a must to satisfy the user. Fixer is a compact and straightforward API that displays past and current currency rates. Because of its dependable information sources for real-time currency rates, SMBs, major corporations, and developers on a daily basis use it on a daily basis. Further, this article will show you that using a currency exchange API is not difficult.

Currency Exchange API It's Not as Difficult as You Think

How is the API Key used?

How would the API response look?

What are the Available Endpoints?

Does it support JSONP Callbacks?

Is it secure?

Does it have Access-Control/CORS?

What do HTTP ETags do?

How do I recognize the potential errors?

What can Fixer help you with?

How is the API Key used?

You need an account in Fixer to start with the Fixer API. The API key is a unique key assigned to your account. It authenticates the account with the Fixer API. Also, the API key restricts your access to endpoints based on the subscription you bought. The API key is provided into the ‘access key’ argument of the API base URL as mentioned below,

https://data.fixer.io/api/latest

? access_key = API_KEY

& base = USD

& symbols = GBP,JPY,EUR

The user gets the latest exchange rates on the requested currencies (GBP, JPY, EUR) relative to USD after the above request is sent if the access key is valid. Also, it should be noted that the rates update in different periods such as 60 minutes, 10 minutes, 60 seconds, depending on the user’s subscription.

How would the API response look?

The API response is the result triggered once the endpoint is called. The Fixer API returns exchange rates that are defaulted to EUR. The data is delivered in JSON format, which is easily interpreted by any programming language.

An example API response including several common international currencies, all proportional to USD by giving the ‘base’ parameter as ‘USD’ and time-stamped at the precise time they were collected, can be found below,

{

“success”: true,

“timestamp”: 1519296206,

“base”: “USD”,

“date”: “2022-03-22”,

“rates”: {

   “GBP”: 0.72007,

   “JPY”: 107.346001,

   “EUR”: 0.813399,

   }

}

What are the Available Endpoints?

APIs expose their data through endpoints. Each endpoint of a currency API exposes different types of data or services, such as conversions past rates. Also, note that the availability of the API endpoints depends on the subscription itself. Given below is the list of endpoints available in Fixer and what they can be used for.

Latest rates endpoint – Offers real-time exchange rate information for all existing currencies or a subset of them.

  • Convert endpoint – Allows any amount of currency conversion.
  • Historical rates endpoint – Provides historical data relevant to the specified date.
  • Fluctuation data endpoint – Data on fluctuations between two dates.
  • Time-series data endpoint – Information on daily historical exchange rates between two dates

Finally, to get more details on these APIs, check the documentation.

Does it support JSONP Callbacks?

The Fixer API supports JSONP Callbacks. You can use this functionality to define a function name, provide it as a callback GET parameter to the API, and then have the API deliver your desired API result encapsulated inside of that function. Given below is an example of the API call.

https://data.fixer.io/api/latest

? access_key = API_KEY

& callback = MY_CALLBACK_FUNCTION

We’re requesting the API to utilize the callback name ‘MY_CALLBACK_FUNCTION’ in the example call above. The API response would be encapsulated in the callback function ‘MY_CALLBACK_FUNCTION’.

Is it secure?

How securely an API handles the data transmission is something that should be thoroughly looked upon to avoid unnecessary problems. On Fixer, the paid subscription levels include 256-bit SSL encryption. Merely use the HTTPS protocol rather than the regular HTTP to access the API through SSL.

Does it have Access-Control/CORS?

Security is one of the main considerations when dealing with an API. Browsers block cross-origin HTTP queries launched by scripts for security concerns. Fixer also supports Cross-Origin Resource Sharing (CORS) and Access-Control Headers. Therefore, it allows you to make Cross-Origin HTTP Requests to the Fixer API.

What do HTTP ETags do?

An ETag is a component of the HTTP protocol and is one of the cache validation techniques. An ETag is an identification issued to a data resource on a server, yet it is altered whenever that resource is modified on the server. HTTP ETags is indeed a method of lowering back-end load by only requesting new Fixer data if prices have altered since the last API response.

The API returns one of the following values depending on whether your result set has been modified from your last API request:

  • The results of your first API request, as well as a ‘304 – Not Modified’ HTTP header signifying that nothing has changed.
  • Updated results with a completely different set of ETag and Date variables, which signal that new data was retrieved.

How do I recognize the potential errors?

Any API is prone to error due to different reasons. However, the result response being understandable to the user is important when an error is returned. A JSON error is sent whenever a specified resource is unavailable, or an API request fails for any other cause. A code and description that users can understand accompany all errors. Given below are some common error codes and their description. If you need further information, the documentation is the ideal place to check.

Error CodeDescription
104Monthly API request volume reached
404Requested resource is not available
101User did not supply an API key, or supplied an invalid AIP key. 
103The API endpoint you requested isn’t available.
102This API request is coming from an inactive account.
105The current subscription plan does not support this API endpoint.
106There were no results for the current request.
201Invalid base currency
202There have been one or more invalid symbols given.

What can Fixer help you with?

In conclusion, the Fixer API gives real-time exchange rate information for 170 global currencies, thanks to 15+ exchange rate sources of data. There are numerous endpoints in the API, each addressing a particular use case. The functionalities get the latest exchange rates, currency conversion, historical exchange rate data, fluctuation data, as well as time-series data.

Sign up today and start working with the best currency API!

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Lucy Bennett

Lucy Bennett is a Contributing Editor at iLounge. She has been writing about Apple and technology for over six years. Prior to joining iLounge, Lucy worked as a writer for several online publications.