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What and How about API Call?

What Is An API Call How Can I Make An API Call

APIs are software-to-software interfaces that allow a computer to interact with other computer programs via information networks. This means the application can communicate with other applications and exchange functional information. It enables businesses to use other people’s data or services while maximizing functionality. To integrate and use an API in your app, you need to make an API call or API request. 

But what is an API call, and how can you make one? Read on to learn.

What is An API?

API call - A graphic of an API

APIs (application programming interfaces) are essentially a set of communication methods, protocols, and structures. They serve as software intermediary, enabling two software or apps to communicate, interact, and exchange data. Developers worldwide use APIs to integrate existing functionality of another app into their apps. APIs also enable developers to integrate data from various sources into their apps. 

For example, you can use a weather API to integrate current, historical, and future weather data into your app. This way, you don’t have to collect data from various sources and aggregate it by yourself.

What is an API Call?

An API call, or Application Programming Interface call, is a request made by one software application to an API in order to access its functionality or data. In other words, when an app wants to interact with an API, it makes an API call or request. 

This request typically includes information such as the desired action/operation to be performed and any required parameters. The API then processes the request, performs the specified action, and returns a response. The response contains the requested data or the result of the operation.

For example, if a weather app wants to fetch the weather forecast for a specific location from a weather API, it would make an API call to the weather API. The call will include parameters such as the location coordinates. The weather API would then process the request, fetch the weather data for the given location, and return the forecast information to the requesting application.

Here is an example of an API call made to a weather API:

Here is an example API response:

Results returned by a weather API in response to an API call

How Can I Make an API Call?

a person working with APIs to make API Calls to API clients

Before making API calls, you should first know what an API key is. An API key, short for Application Programming Interface key, is a unique identifier that authenticates a user, developer, or program calling to an API. API keys improve API security by serving as a form of authentication and autorization.

For most APIs, an API key is required to make an API call. Once you have your unique API key, which you can typically obtain by signing up with the API, you can insert it in the API call/endpoint URL. Keep in mind that different APIs have different endpoints. You can typically find information about API endpoints/URLs in the API documentation.

Where Does an API Call Go?

APIs communicate with endpoints. An API Endpoint is a location where an application calls an API. API calls, for example, will reach an API endpoint in a mobile application. The server receives API requests, processes them, executes the responses, and responds.

What are Some Examples of API Calls?

API calls exist everywhere. Let’s see the different types of calls in the API.

Example 1

You must have logged into an app account at some point. Users’ log-in credentials via an app trigger an API call to the server, which grants access. Once the server confirms the user has provided the correct username and password, the user is granted access to the application.

Example 2

Another scenario in which API calls should be considered is when purchasing movie tickets. When users enter information about their movie plans (such as dates and seating arrangements), an API call is made to evaluate the request, gather data from the cinema’s database, and return real-time availability and pricing information to the user. 

Example 3

Similarly, API calls are made when one checks the exchange rates of a currency or the status of some location in the world. Another well-known API is Google Maps, which many across the world use daily. It makes multiple API calls without any faults and is the perfect example of a robust API.

What are Some API Call Parameters?

API call parameters are additional information included in an API request to provide context, specify options, or provide data needed to perform the request.

Here are common types of parameters often included in API calls:

  • Query Parameters: These parameters are added in the API URL query string. They help specify filtering criteria, sorting options, etc.
  • Header Parameters: These parameters are added in the HTTP headers of the request and provide metadata about the request. This can include authentication tokens, language preferences, and content types.
  • Path Parameters: These parameters are typically a part of the URL path. They help specify variable parts of the resource being accessed.

How Can You Test API Calls?

A graphic of software testing

APIs are available for almost any application. For example, there is an API for embedding Instagram photos into your website to provide access to millions of images. However, it is critical to thoroughly evaluate the various API options to see if they can meet the needs of your app. Testing is essential in the development of the API. API functions are frequently tested to ensure they are available and meet consumer expectations. 

How is API Testing Done?

API testing entails making an API call to a different endpoint and receiving a response that validates the status code, response duration, and data in the response. This test is typically performed using an online application, such as ReqBin. While the process is nearly identical for all APIs, the steps will differ depending on your tool.

Here are the steps for testing a REST API:

Select The Appropriate HTTP Method

When testing an API call, choosing the right HTTP method is essential. For example, you would use the GET method to retrieve data from the server. A REST API typically supports four HTTP methods: GET, PUT, POST, and DELETE. 

Enter Your Credentials In The Authorization Tab

When APIs require authorization, you must enter the credentials in the authorization tab. 

Enter the URL of the API Endpoint

Usually, it is provided in the API’s documentation. A good API would even have some examples of how to use the API endpoint and details about the relevant parameters.

What Is An API Marketplace, And What Is An Example Of One?

APILayer API marketplace

An API marketplace is a platform that brings together API suppliers and customers. A provider and developer portal are two components of an API marketplace. API sellers (developers or companies) can advertise their APIs for sale on an API marketplace, and API buyers (other developers) can view and purchase them. These markets may be considered API listings.

An example of a good and reliable API marketplace is the APILayer API marketplace. APILayer is a market leader in the API space, with over 15 years of experience creating and delivering safe APIs. The marketplace has over 100 different APIs for different purposes. Moreover, it enables developers to promote their APIs to a global audience and monetize them. 

Now that you know all about API calls, you can use APIs offered by APILayer to create scalable applications and integrate API functionality in just a few minutes.


An API call refers to a request made by one application to an API to access its functionality or data. APIs communicate with endpoints, which is where the API call originates. When an API receives a request, it processes the request, performs the specified action, and returns a response. API requests often also contain parameters providing additional information. Common parameters include query parameters, header parameters, and path parameters.


What are REST API calls?

REST API calls are API requests made to a REST API. These APIs typically support four HTTP methods: GET, PUT, POST, and DELETE. An API call is when a server requests an endpoint on its website. For example, sometimes logging onto an app or asking questions using a browser is an API call. Similarly, you can make API calls to request data, such as weather data.

What is an API HTTP request?

HTTP-based API calls refer to sending API calls/requests using the HTTP (Hypertext Transfer Protocol) protocol.

What is API full form? 

API is an acronym for Application Programming Interface. They function as software intermediaries, allowing two software applications to communicate with one another. For example, an API is used when you use Facebook or check the weather on your mobile device.

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