Ppapi application programming interfaces

Published: 09 April 2024
Contributor: Michael Goodwin

An API, or application programming interface, is a set of rules or protocols that enables software applications to communicate with each other to exchange data, features and functionality.

APIs simplify and accelerate application and software development by allowing developers to integrate data, services and capabilities from other applications, instead of developing them from scratch. APIs also give application owners a simple, secure way to make their application data and functions available to departments within their organization. Application owners can also share or market data and functions to business partners or third parties.

APIs allow for the sharing of only the information necessary, keeping other internal system details hidden, which helps with system security. Servers or devices do not have to fully expose data—APIs enable the sharing of small packets of data, relevant to the specific request.

API documentation is like a technical instruction manual that provides details about an API and information for developers on how to work with an API and its services. Well-designed documentation promotes a better API experience for users and generally makes for more successful APIs.

Learn how intelligent automation can make your business operations a competitive advantage.

Register for the guide to operationalize FinOps

It’s useful to think about API communication in terms of a request and response between a client and server. The application submitting the request is the client, and the server provides the response. The API is the bridge establishing the connection between them.

A simple way to understand how APIs work is to look at a common example—third-party payment processing. When a user purchases a product on an e-commerce site, the site might prompt the user to “Pay with PayPal” or another type of third-party system. This function relies on APIs to make the connection.

• When the buyer clicks the payment button, an API call is sent to retrieve information. This is the request. This request is processed from an application to the web server through the API’s Uniform Resource Identifier (URI) and includes a request verb, headers, and sometimes, a request body.
  
• After receiving a valid request from the product webpage, the API calls to the external program or web server, in this case, the third-party payment system.
  
• The server sends a response to the API with the requested information.
  
• The API transfers the data to the initial requesting application, in this case, the product website.

While the data transfer differs depending on the web service used, the requests and responses all happen through an API. There is no visibility on the user interface, meaning APIs exchange data within the computer or application, and appear to the user as a seamless connection.

APIs can be categorized by use case, including data APIs, operating system APIs, remote APIs and web APIs.

Used to connect applications and database management systems.

Used to define how apps use operating system services and resources.

Used to define how applications on different devices interact.

Used to enable data and functionality transfer over the internet using HTTP protocol.

Today, most APIs are web APIs. Web APIs are a type of remote API (meaning that the API uses protocols to manipulate external resources) that expose an application's data and functionality over the internet.

The 4 main types of web APIs are:

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 connect strategic business partners. Typically, developers access these APIs in self-service mode through a public API developer portal. Still, they need to complete an onboarding process and get login credentials to access partner APIs.

Internal, or private, APIs remain hidden from external users. These private APIs aren't available for users outside of the company. Instead, organizations use them to improve productivity and communication across different internal development teams.

Composite APIs combine multiple data or service APIs. They allow programmers to access several endpoints in a single call. Composite APIs are useful in microservices architecture where running a single task might require information from several sources.

Because APIs allow organizations to open access to their resources while maintaining security and control, they have become a valuable aspect of modern business and personal applications.

Here are some API examples that users often encounter:

A popular API example is the function that enables people to log in to websites by using their Facebook, X, or Google profile login details. This convenient feature allows any website to use an API from one of the more popular services for quick authentication. This capability helps save users the time and hassle of setting up a new profile for every web application or new membership.

These “smart devices” offer added functionality, such as internet-enabled touchscreens and data collection, through APIs. For example, a smart fridge can connect to recipe applications or take and send notes to mobile phones through text message. Internal cameras connect to various applications so that users can see the contents of the refrigerator from anywhere.

Travel booking sites aggregate thousands of flights, showcasing the cheapest options for every date and destination. APIs enable this service by providing application users access to the latest information about availability from hotels and airlines.

This access is available either through a web browser or the travel booking company’s own application. With an autonomous exchange of data and requests, APIs dramatically reduce the time and effort involved in checking for available flights or accommodation.

Navigation apps use core APIs that display static or interactive maps. These apps also use other APIs and features to provide users with directions, speed limits, points of interest, traffic warnings and more. Users communicate with an API when plotting travel routes or tracking items on the move, such as a delivery vehicle.

Social media companies use APIs to allow other entities to share and embed content featured on social media apps to their own sites. For example, the Instagram API enables businesses to embed their Instagram grid on their website and for the grid to update automatically as users add new posts.

APIs are an integral part of the growth in software as a service (SaaS) products. Platforms like CRMs (customer relationship management tools) often include several built-in APIs that let companies integrate with applications they already use, such as messaging, social media and email apps.

This integration drastically reduces time spent switching between applications for sales and marketing tasks. It also helps reduce or prevent data silos that might exist between departments that use different applications.