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Beginner Guide: What is an API?

Beginner Guide: What is an API?

You definitely heard about something called API. Whether you manage a website or plan to build your digital product, you must grasp what an API is and why it is vital to any organization and development project. This article is here to help.

What is API Mean?

Thanks to Application Programming Interface, or API, all that data could be put together to match your requests. Employing an API underpins much of our digital lives and enables the creation of numerous online businesses and services.

While APIs may appear quite sophisticated when spoken about, they are relatively simple.

By definition, an API, or Application Programming Interface, is a collection of rules and protocols that enable various software systems to communicate with one another. It acts as a bridge between software systems, allowing them to share data and carry out specific tasks.

Now, let’s simplify the concept with a metaphor. You are sitting at your table in a restaurant, and you call the waiter as you’re ready to order. He takes notes about what you would like to have and then goes to the kitchen to let the chefs know. They prepare your meal, and the waiters pick it up and deliver it to your table. You stayed at your table; the chefs stayed in the kitchen, yet they prepared what you wanted. This happened thanks to the waiter, who acted as a messenger. Well, the waiter is the API.

In essence, the API is a messenger that transports data from one location to another. APIs are omnipresent, and they come in a variety of shapes and sizes.

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How Does an API Work?

The process of API work includes a request, one or more target application activities, and an API operation response. The flow is started by invoking the API operation, which may be done from mobile or online apps.

The process involves developers, the API, resources/assets, and finally, the end user:

  • Developers access resources through a company’s API to create mobile or Web App
  • The API provides access to the shared resources, allowing developers to connect their apps and their data;
  • The resources such as data, software, and brands are leveraged by partners, developers, and third-party services that can use the API;
  • End users use the apps and websites, which, through the API, can provide richer experiences by leveraging the data and services of other apps and sites.

This is how API generally works. However, different APIs have protocols, specifications, and operational mechanisms.

Types of API

A broad category is Web API. It includes APIs that are accessible over the HTTP protocol. This is a very general category since when developers discuss APIs, they nearly invariably refer to web-based APIs used to interact between two computers linked remotely over the internet.

The main categories by the audience

  • Public APIs are accessible to the general public (open source), typically provided by businesses to allow developers or anybody access to their services and data.
  • Private APIs are only available to those who have been granted access. Businesses often use them to deliver services to their clients or business partners.
  • There is a further category between private and public APIs referred to as partner APIs. They frequently serve to transfer data between two corporations or organizations for a specific commercial purpose while maintaining rigorous privacy protection.

Depending on the type of digital product or service, there are specific APIs. Architectures and protocols distinguish these.

APIs according to the type of Architecture

  • Monolithic APIs, the most familiar to developers, frequently resemble the design of a relational database or MVC (model-view-controller) application. They serve many distinct use cases, providing predictable functioning over various resources while staying stable over time. Yet, as the name indicates, monolithic APIs can be difficult to scale or rework because so much data is interrelated inside them.
  • Microservices APIs are more typical for internal and partner APIs. Most CI/CD (continuous integration/continuous deployment) development teams employ several microservices as part of their code lifecycle, each providing a distinct, independent role. Microservices APIs have a clear disadvantage in that they create a massive number of individual API requests.
  • Composite APIs allow access to numerous API endpoints with a single call. APIs frequently include overlapping data at several endpoints, and a composite API can expedite API calls by selecting the most efficient combination of requests to deliver the required data. Thus, it provides more data quality while reducing data volume by providing a single payload to many endpoints. Moreover, composite APIs may group calls for similar use cases, such as generating a new user account.
  • Unified APIs are similar to composite APIs in combining related calls to many APIs rather than various endpoints on a single API. Partner APIs frequently use unified APIs.

Main APIs types by protocol

The protocol specifies how your API connects and communicates with the internet. The protocol influences the design and maintenance of an API. It is, therefore, critical to understand each option. The most significant ones in software engineering right now are:


Representational State Transfer (REST) APIs make web applications and data access. REST is an architectural approach that may be used in API management as an alternative to microservices architecture. These APIs employ the HTTP protocol, a standardized method of sending data over the internet, and may be used with any language or platform that an HTTP library supports. REST APIs are pretty popular, and they were the de facto norm for establishing backend APIs for a long time. These APIs are still utilized for a wide variety of services. However, working within the limits of REST and HTTP requires some creativity.


Simple Object Access Protocol APIs are a more rigorous type of API. SOAP APIs can only operate with XML data and have stricter request conditions. SOAP requests also demand more bandwidth than REST, and developing and maintaining SOAP code is more complicated. On the other hand, SOAP is also extendable and supports many internet communication protocols, including HTTP, SMTP, and TCP/IP. It allows developers to design APIs in various styles and add features and capabilities. One significant advantage of SOAP is that it needs metadata files to describe requests, making exchanges more predictable. It also supports stateful requests, as opposed to REST, which is stateless. As a result, SOAP APIs are more secure, which is why they’re commonly used in finance and significant corporate applications.


The Remote Procedure Call (RPC) protocol provides a straightforward method for sending and receiving information. It varies from SOAP and REST APIs in several essential aspects. As the name implies, this protocol calls for a procedure rather than a data resource. Whereas a RESTful API produces a document, an RPC server’s response is either confirmation that the function was triggered or an error explaining why it did not run. In other words, a REST API handles resources running executable operations or processes, whereas an RPC API handles actions and primarily exchanges data. RPC may use two alternative languages for coding: JSON and XML.

4. GraphQL APIs

GraphQL is not a protocol in itself. It is a unique query language with best practices for its use. GraphQL, like a REST API, uses HTTP to deliver text data in the payload of each request, but it takes a different method. GraphQL has a single endpoint, and the needed data is specified in the request. In comparison to the tight routing restrictions of a REST API, GraphQL gives consumers a lot of freedom inside a single query. It can also make data caching difficult and makes the API consumer accountable for maintaining consistent query syntax to obtain similar data. For this reason, a faster deployment or integration requires a more formulaic protocol like REST.

The type of an API can have a significant and long-term influence on its success and acceptance. Companies must choose the best format based on the following:

1) the complexity of the information to be communicated

2) the amount of security necessary

3) the speed or performance required from those exchanges.

API developer

Common Uses of APIs

APIs are the key to the success of many modern software systems. End users enjoy the benefits of APIs daily on many apps and websites. Let’s see now the most common and identifiable examples of current API use cases. Yet, many APIs created for commercial partners or internal use benefit the companies but are never widely adopted.

Login and authentication

In today’s highly networked software environments, login and authentication APIs provide some form of single sign-on. For example, one may urge users to “log in using Facebook.” Users no longer need to create a different account for each site or application, and the API involved efficiently integrates multiple application authentication behind the scenes.

Social media and messaging apps

APIs are used by social media platforms like Twitter and Facebook to manage communication between the platform and remote endpoints like Twitter bots.

Financial and payment transactions

A bank frequently uses an API to connect remote users to the bank’s backend systems for remote deposits, balance checks, transfers, and electronic payments. PayPal, for example, employs an API to connect a user to a PayPal account and even to make payments to third-party retailers such as Amazon and eBay.

Travel and booking

Consumers who look up airline schedules and buy tickets use the airline’s API, while those who look up hotel availability and book rooms use the hotel’s API. Some sites use proprietary APIs to allow clients to search for and book different flights and lodgings, while the travel site uses airline, hotel, car rental, and other provider APIs on the back end.

Content distribution and administration

Online content delivery platforms, such as Spotify and Netflix, use APIs to allow users to select desired content and then deliver that streaming content to the user’s device for viewing. At the same time, the provider retains control over the content, which is never actually downloaded or stored on the user’s device.

Shipping and supply chain management

The process of packing and delivering an item from the point of origin to the end of the destination generates a large amount of real-time data. APIs allow customers to verify the progress of a purchase and view any shipping data, such as the package’s current position and expected arrival date.

Widgets and services

APIs are typically utilized to implement many minor features and operations. For example, the weather report, ocean tide schedule, news feeds, and other information in a web search are frequently built by connecting to numerous service providers using the search engine’s APIs. APIs are used by certain services, such as Google Maps, to allow users to search for locations or plan routes via their web browser, and APIs also enable maps to be incorporated into a wide range of third-party websites.


From the standpoint of software development, APIs are critical components of modern microservices-based systems, allowing communication among the multiple modules or containers developed to build the program. As a result, while one module can be edited, testing and updating are confined to that module or microservice.

These are only a few examples of typical applications. As the importance of software develops, API cases will continue to explore new use cases and play an increasing role in software development.

API illustration devices

Why Do We Need an API?

Today, almost all economies are quickly transitioning digitally to compete and meet increasing customer demands. Telehealth, education, finance, and entertainment face the most radical technological advancements.

APIs assist businesses and organizations in digitizing, connecting, and innovating their products and services. A wide variety of APIs are used in today’s workplace, mobile, and online software, and they help to:

  • Simplify and expedite their market entry tactics
  • Improve client interactions
  • Increase synergies between companies
  • Increase operational agility and speed
  • Create and seek new income, market, and distribution channels
  • Manage large amounts of data and integrate data across multiple platforms

As a powerful and adaptable tool for connecting different software applications, APIs enable various unrelated software products to interact and communicate with other applications and data. Therefore, organizations get access to their data by making it publicly available.

Most API use cases involve merging data from different sources to create new goods and services, like our initial examples of flight websites and rental apps with integrated maps. This is possible via APIs that interface with many operating systems, such as iOS. This allows the organization to broaden its customer support reach while improving the user experience. Thanks to these APIs, end users access their app accounts, check their order history, and track and buy their products in seconds. We can get all this information in real time without contacting customer support.

APIs come in handy for businesses managing large amounts of data, enabling quick collection and analysis. This facilitates interaction by enhancing communication within a company and between firms.

To sum up, we need APIs because they enable interactions between applications and devices such as smart TV services, earphones, automobiles, etc. Therefore, the reason why we do need APIs is simply that they work.

APIs for Real-time Communication

From business to daily interactions, real-time communication (RTC) is standard. Thanks to Internet technology, it has become as fast as now and extensively uses APIs. Chatting, video chatting, live streaming on social media, and talking to our doctor on telehealth apps are all possible thanks to these APIs.

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These are often called real-time communication APIs, as they specifically refer to changes in an environment in real time, regardless of whether the environment is physical (natural processes) or virtual (instant messaging, social media). Data from a real-time communication API is differentiated from archived or historical data and processed within seconds or milliseconds.

Common Real-time Communication APIs

  • In-app chat APIs allow businesses and organizations to integrate chat into their services. These facilitate communication, which is instant and efficient. For example, they are a norm for financial, health, and educational institutions. Today, they guarantee better service that banks can provide their customers. These APIs also allow participants in a chat, such as group chats.
  • Utilizing video calling API simplifies and personalizes interactions between individuals, employees, enterprises, and organizations. The traditional real-time communication experience has been changed by video calls and conferences. APIs enable multiple users’ to video conference and even use interactive tools, which are essential in educational and telehealth app settings.
  • Voice chat API is another fantastic interactive way to converse instantaneously. Several applications nowadays, from chatting to shopping to banking, have this choice. A voice chat API enables voice chats as well as recorded voice messages. In voice chat rooms, voice chat can happen with many people simultaneously.
  • Livestreaming APIs enable live video streaming, a trendy way to create and consume content online.

ZEGOCLOUD Real-time Communication APIs

ZEGOCLOUD is the world’s largest provider of cloud real-time communication services. This vendor ensures seamless, dependable audio and high-quality video experiences even in poor network situations by enabling organizations and developers to simply and rapidly access real-time audio and video communication capabilities.

Its APIs provide developers a diverse selection of RTC products and solutions, extending beyond traditional RTC APIs into the unique cutting-edge domain of Real-time Interaction and metaverse Avatar. APIs available for:

  • Voice and Video Call
  • In-app Live Streaming
  • In-app Chat
  • AI Effects
  • Virtual Avatar
  • Super Board
  • Cloud Recording

Find the entire ZEGOCLOUD API offering with full documentation for every available client and server-side API.


Not only APIs, but ZEGOCLOUD also offers SDKs and UIKits to customize and enrich clients’ apps. As a leading cloud communications provider, ZEGOCLOUD is dedicated to delivering better service value for the greatest real-time engagement experiences.

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