What is an API? The Complete Guide

Many people working in technology knows what an API (application programming interface) is but explaining it can be tricky. In a nutshell, an API is a part of computer code and a piece of server software.  

APIs set the rules for how applications share data, much like how protocols set the rules for data exchange over networks. Without APIs, it would be much more difficult for software developers to write code that retrieves information from different platforms or apps.  

We'll go into detail on what an API is in this blog.

What is an API?

An application programming interface, or API, is a collection of guidelines that permits data sharing, feature sharing, and communication between software programs.

APIs make software development easier and faster by allowing developers to use data and services from other applications instead of creating them from scratch. They also provide a secure way for application owners to share their data and functions within their organization or with business partners and third parties.

By only sharing necessary information and keeping other system details hidden, APIs help enhance security. They allow servers or devices to share small, specific pieces of data rather than exposing everything.

API documentation is like a technical manual that explains how an API works and guides developers on how to use it effectively. Good documentation leads to a better user experience and contributes to the success of the API.

How API Works?

API communication is a request and response between a client and a server. The client is the application making the request, and the server responds. The link between them is the API.

Think about third-party payment processing to understand how APIs operate. APIs are at work when you buy something on an e-commerce site and choose to “Pay with PayPal” or another system.

When you click the payment button, the site sends an API call to retrieve information. This call is the request. The Uniform Resource Identifier (URI) of the API is used to transfer the request from the application to the web server. It is composed of headers, a request verb, and sometimes a request body.  

The third-party payment system or other external application is contacted by the API, which then gets the request and sends it to the web server.

The server then provides the necessary data in response to the API.

This data is returned to the originating application—such as the product website—by the API.

All queries and answers go through an API, despite data transport methods differing. This process is invisible on the user interface, so it looks like a smooth, seamless connection to the user.

What Can an API Do?

A better question might be, what can’t APIs do? Do you want to use Instagram images on your online store? An API is available for it. Do you want to provide readers of your travel blog with fast access to thousands of hotels? For that, there is also an API.

Here are some common business uses for APIs:

Data Sharing

An API is used whenever a program needs to fetch data from a third party, like a travel app getting flight times from airlines.

App Integrations

An API usually connects when two apps work together, like HubSpot and Gmail.

Embedded Content  

To embed content from another site, like a YouTube video, an API request is made to pull in the content.

Internal Systems

Data exchange with other sources isn't the only use for APIs. Businesses use them to connect different internal software parts, especially in a microservice setup.

Example of APIs

Chances are, you've come across some APIs without even realizing it or delving into an API marketplace. Let's look at a few examples:

X APIs

If your company is big on X formerly known as Twitter, you can use its APIs to boost engagement on your website. X offers a range of APIs that let you explore its vast archive. You can manage ad campaigns, find old Tweets, and integrate timelines on your website with X's APIs. Plus, these APIs can help you:  

  • Stay updated with real-time X posts using filtering and streaming feature
  • Deliver tailored customer support by engaging in direct message conversations
  • Receive instant updates from more than 15 accounts through webhooks

Also, there is a wealth of technical resources and tools with documentation available. These can guide you in making the most of X's global communication network.

YouTube APIs

YouTube APIs empower users to enhance their website's features and tap into YouTube's vast video library.  

Consider these innovative applications for using YouTube's APIs:

  • Seamlessly integrating video playback directly into your app
  • Enabling people to upload their own movies and conduct content searches
  • Efficiently manage and curate playlists tailored to your audience's interests
  • Obtaining insightful knowledge on how viewers interact with your videos and channel
  • Arranging and overseeing live broadcasts to interact with viewers in real time

Instagram APIs

Instagram’s platform provides various APIs to support your business with content publishing and metrics tracking tasks.  

A great example is embedding user-generated Instagram photos into your app. User-generated content (UGC) can influence potential buyers through strong social proof.  

Using this platform, developers produce services and apps targeted at three primary groups:

  • People who desire to distribute their content through applications from other parties
  • Brands and advertisers seek to comprehend and control their audience and media rights
  • Broadcasters are interested in discovering content, obtaining digital rights to media, or sharing it with proper attribution

Spotify Web APIs

The Spotify Web API is worth looking at if you work in the music business. It makes integrating music player features into your website or app easy.

You have complete access to the Spotify Data Catalog, which includes albums, artists, and songs, thanks to Spotify's wide range of APIs. Users need to authorize your app to access user-related data like private playlists.  

The functionalities closely mirror those found on the native Spotify platform. For instance, the Browse API allows your users to explore genres, categories, new releases, and personalized playlist recommendations.  

Google Maps APIs

For anyone developing a location-based app, the Google Maps APIs are indispensable. For instance, if you're creating a real estate app, you can integrate Google Maps APIs to showcase a street view of properties.

Google's platform boasts a rich library of APIs with myriad applications. Need to enable users to request directions? Interested in incorporating Places into your website? A ridesharing app developer can even use a specific API. You may choose the right API for your project by using the categories provided by Google based on usage and platform (web, iOS, or Android).

As with most examples, these APIs are priced based on monthly usage. However, their extensive functionality makes them a worthwhile investment.

Types of APIs

According to their intended uses, APIs may be divided into several groups. Let’s have a look at them:

  • Data (or database) APIs: These are utilized to link applications with database management systems, facilitating seamless data exchange
  • Operating system (local) APIs: These APIs dictate how applications utilize services and resources within an operating system
  • Remote APIs: These define the interaction between applications on various devices, enabling communication and data exchange over networks
  • Web APIs: These allow the HTTP protocol to be used to convey data and functionality across the internet.

Most APIs today are web APIs. These remote API types allow applications to share their data and features over the internet.

There are four main types of APIs:

Open APIs

External parties use public APIs, sometimes referred to as open APIs. Certain open APIs are free to use, but others could have a membership cost that is usually based on consumption.

Partner APIs

Relationships between strategic corporate partners are facilitated via partner APIs. Typically, developers may access these APIs through a public API developer site and work on their own projects. They must, however, complete the onboarding procedure and get access credentials to use partner APIs.

Composite APIs

Programmers may access numerous endpoints with a single request thanks to composite APIs, which integrate various data or service APIs. These APIs are useful in microservices architecture, where it can be necessary to collect data from several sources to complete a single job.

Internal APIs

External users cannot access internal or secret APIs, and they are concealed from outsiders. Organizations use these APIs internally to enhance productivity and communication among various development teams within the company.

How to Use an API?

So, do you want to give APIs a try? Before you start making your own, it's a good idea to use ones made by other people.

Find an API

First, pick an API to use in your business. You might already have one in mind, especially if you're eyeing big ones like Facebook's API. You can also search by cost, starting with free APIs before moving to paid ones. Once you've chosen an API, dive into its documentation.

Pick How You'll Access it

You have a few choices for accessing an API. You may utilize user credentials, authentication tokens, or an API key.

An API key shows you're a legit user, sets your access permissions, and keeps track of your interactions with the API.

Some APIs offer keys for free, while others charge for them. You will most likely need to register for the service to obtain your special key, which you will mention throughout.

Keep your key secret, like a password. Someone could make API requests pretending to be you if it gets out. You might be able to get a new key and cancel your old one if that happens.

Read the API Docs

An API's user manual is like its documentation. It offers lessons and examples along with an explanation of how to utilize the API.

Check out the documentation to learn how to get your key, send requests, and fetch resources from the server.

Good API documentation is super important. Even if a company has a great API, it's not much help if developers can't figure out how to use it quickly.

Connect Your App

Now that you know how to request your chosen API, you can link your app to it. A developer with knowledge of Python, Java, JavaScript (including NodeJS), PHP, and other languages would be qualified for that position.

The API you're dealing with is probably a type called a REST API, which tends to be easier to work with than others.

REST Vs. SOAP

There are two distinct ways to create APIs: SOAP and REST. Each has standards and guidelines for how APIs should communicate with other apps. Whereas SOAP is a protocol, REST is a restricted architectural style. HTTP is used by both for information exchange.

REST is clear, lightweight, versatile, and reasonably easy to use, which makes it a more straightforward protocol than SOAP. However, SOAP typically requires more code to accomplish tasks than REST.

Due to its type-checking, SOAP is known for being more deterministic and robust. Many developers argue that SOAP is easier to use because it's supported by various development tools. SOAP is also considered more secure and suitable for strict data integrity scenarios.

Whereas SOAP is restricted to XML, RESTful systems allow communicating in plain text, HTML, YAML, XML, and JSON. Every strategy has advantages, and the particular use case may determine which one is best. However, one reason REST is frequently used for developing public APIs is its capacity to accommodate a variety of data types.

Conclusion  

In essence, an API is a mechanism that lets two apps talk to one other by exchanging certain data. APIs are crucial in modern business and personal projects because they enable companies to share resources while maintaining security and control. Understanding APIs is important for anyone involved in technology or software development.