Application programming interfaces, or APIs, simplify software development and innovation by enabling applications to exchange data and functionality easily and securely.

What is an application programming interface (API)?

An application programming interface, or API, enables companies to open up their applications’ data and functionality to external third-party developers, business partners, and internal departments within their companies. This allows services and products to communicate with each other and leverage each other’s data and functionality through a documented interface. Developers don’t need to know how an API is implemented; they simply use the interface to communicate with other products and services. API use has surged over the past decade, to the degree that many of the most popular web applications today would not be possible without APIs.

application programming interface

Why would we need an API?

Here, are some reasons for using the Application Programming Interface:

  • Application Programming Interface acronym API helps two different software’s to communicate and exchange data with each other.
  • It helps you to embed content from any site or application more efficiently.
  • APIs can access app components. The delivery of services and information is more flexible.
  • Content generated can be published automatically.
  • It allows the user or a company to customize the content and services which they use the most.
  • Software needs to change over time, and APIs help to anticipate changes.

How do APIs work?

Application Programming Interface architecture is usually explained in terms of client and server. The application sending the request is called the client, and the application sending the response is called the server. So in the weather example, the bureau’s weather database is the server, and the mobile app is the client.

There are four different ways that APIs can work depending on when and why they were created.

  • SOAP APIs: These APIs use the Simple Object Access Protocol. Client and server exchange messages using XML. This is a less flexible API that was more popular in the past.
  • RPC APIs: These APIs are called Remote Procedure Calls. The client completes a function (or procedure) on the server, and the server sends the output back to the client.
  • Websocket APIs: Websocket API is another modern web API development that uses JSON objects to pass data. A WebSocket API supports two-way communication between client apps and the server. The server can send callback messages to connected clients, making it more efficient than REST API.
  • REST APIs: These are the most popular and flexible APIs found on the web today. The client sends requests to the server as data. The server uses this client input to start internal functions and returns output data to the client. Let’s look at REST APIs in more detail below.

Types of Application Programming Interface

Nowadays, most application programming interfaces are web APIs that expose an application’s data and functionality over the internet. Here are the four main types of web API:

  • Open APIs are open-source application programming interfaces you can access with the HTTP protocol. Also known as public APIs, they have defined API endpoints and request and response formats.
  • Partner APIs are application programming interfaces exposed to or by strategic business partners. Typically, developers can access these APIs in self-service mode through a public API developer portal. Still, they will need to complete an onboarding process and get login credentials to access partner APIs.
  • Internal APIs are application programming interfaces that remain hidden from external users. These private APIs aren’t available for users outside of the company and are instead intended to improve productivity and communication across different internal development teams.
  • Composite APIs combine multiple data or service APIs. These services allow developers to access several endpoints in a single call. Composite APIs are useful in microservices architecture where performing a single task may require information from several sources.

application programming interface

Application Programming Interface examples

There is plenty of public APIs out there for you to interact with, many from industry behemoths. The ability to access some platform company’s code programmatically via an API is what makes them a platform, in essence. Some prominent API examples include:

  • Google APIs, allow you to connect your code to the whole range of Google services, from Maps to Translate. APIs are so important to Google that they acquired Apigee, a leading API management platform.
  • Facebook APIs, allow you to programmatically access Facebook’s social graph and marketing tools. (The company has been restricting just what user data you can access via these APIs in the fallout from Cambridge Analytica and other scandals.)

To get a sense of how APIs work, let’s do a deep dive into two: the Java API, which Java developers use to interact with the Java platform, and the Twitter API, a public API that you would use to interact with the social networking service.

The Future of APIs

These small software intermediaries enable the huge transformational potential for any company, large or small. The ability of programmers to connect different applications and systems to form a cohesive, stable software solution is almost limitless. Using components to create software, rather than building from scratch, means expensive and time-consuming specialized software developments may be a thing of the past.

The future of APIs is in artificial intelligence (AI) and machine learning. AI is developing autonomous software that exposes its interface and registers itself with an API database, where it finds a relevant API and installs it, without any human interference.