What Is API And How Does It Work In Simple Terms

What Is API And How Does It Work In Simple Terms

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What Is API And How Does It Work In Simple Terms

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As humans, we use words, gestures, and facial expressions to convey our ideas, desires, and thoughts. To interact with one another, software or its parts do not require a graphical user interface. APIs, or Application Programming Interfaces, are machine-readable interfaces that allow software products to communicate data and functionality.

Today, we will talk about APIs in detail: what is an API, what are the different types of APIs, what are the different purposes of APIs, and so on. So, don't miss a single heading in this article!

What you will learn from this article:

  • What is the primary purpose of an API?
  • How does an API work in the context of software communication?
  • What are the key components of an API request?
  • Why are APIs important for modern software development?
  • Difference between API and web services?
  • What are some common challenges in producing and consuming APIs?
  • What are the different types of APIs based on availability?

What is an API?

APIs are programming interfaces that connect platforms or programs, allowing them to make queries and exchange data. They lay forth a set of guidelines and procedures that will govern how these platforms interact.

The programming interfaces ensure that various types of programs may communicate with one another by specifying particular actions. This makes it easier to integrate diverse solutions so that ready-made functionalities can be used in other applications.

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How does an API Work?

Here's how an API works:

  1. To gather information, a client application makes an API call, also known as a request. This request, which comprises a request verb, headers, and occasionally a request body, is sent from an application to the web server through the API's Uniform Resource Identifier (URI).
  2. The API sends a request to the external software or web server after getting a verified request.
  3. The server responds to the API.

Diagram of how the API works and what is API endpoint

The data transmitting process differs based on the services. The requests are handled through an API. They are meant for computer or program usage, whereas user interfaces are built for humans to use.

Why Do We Need an API?

Investing in APIs simplifies the work of developers. It enables a solution to be incremented using pre-written code, eliminating the requirement to program each component that your program/application requires from the beginning.

APIs are rapidly being used to bring pre-built functionality to creative approaches, resulting in better user experiences. APIs are widely used for these and other reasons.

APIs are great because they provide:

  • Greater control over permissions for access to software and hardware.
  • New income sources, such as API monetization.
  • Adaptability in system and application integration
  • Decreased coding time for developers.
  • Enhances the user experience with digital items.
  • Internal process simplification.
  • Shortening the time it takes for digital solutions to reach the market

What is the Difference between API and Web Services?

The distinction between APIs and so-called web services is a source of confusion among programmers. First, we must recognize that every web service is an API, but not every API is a web service.

Isn't it puzzling?

Web Services are a sort of API that uses an integration paradigm that predates the current one. However, as the forerunners of Application Programming Interfaces, they have restrictions on the most current interfaces.

A benefit of web services is that they are frequently coupled to perform complicated requests, namely those that utilize the HTTP (HyperText Transfer Protocol) protocol, which is responsible for data transfer on the internet and websites with HTML code structures.

What is an API Request?

API requests it must have various components

For an API Request to work, it must have various components. Let's look at each one and see how they can be combined to create a request.


When making an API call, an endpoint has two important components. The URL is one of them. For all its API calls and API Requests, BigCommerce utilizes the URL https://api.bigcommerce.com/stores/. This may appear to be a legitimate URL; however, it will result in a 404 error message when entered into a web browser.

The path is the second element. Depending on what you want to accomplish, the path will be different. Visit the developer documentation at https://developer.bigcommerce.com/api-reference to get a list of possible routes for BigCommerce. We'll use the /v3/catalog/products path for this example. We obtain a full endpoint https://api.bigcommerce.com/stores/%7B$$.env.store_hash%7D/v3/catalog/products when we combine these two elements. You must be wondering, "What is the store hash?" "Where did you get that?" This is referred to as a variable. Variables are one-of-a-kind components of an endpoint that will change depending on the information in your store. The open and closed brackets "{ }" indicate a variable.

Headers give the client and server information. Authentication credentials such as an "Auth Token" or "Client ID" are common header examples. When you establish an API Account, you will be given these credentials immediately. The "Content-Type" header is another frequent header that tells the server what type of content will be delivered. For example, "application/JSON" is a typical content type that informs the server that we deliver JSON data.


These are the actions taken when sending a request. GET, PUT, POST, and DELETE are all API Methods.


The request data, often known as the "body," is information a server will send to or return. Here's an example of API data from the preceding JSON topic. Before being provided, the body of a request may require further information. If you are updating a single product, for example, you will need the Product ID before making any changes.

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Different Kinds of APIs

There are different types of APIs, which can be classified as:

APIs By Availability

APIs can be private, partner, and public.

Private APIs

These software interfaces intend to help organizations improve their products and services. In-house developers or contractors mostly use these APIs contractors to integrate a company's IT systems and applications and create new systems or customer-facing apps that use current systems. Even though the applications are open to the general public, the interface is only accessible to those working directly with the the API provider or publisher. A company can use the private approach to have complete control over API usage.

Partner APIs

Partner APIs are marketed freely but only shared with business partners who have signed a publishing contract. Software integration between two companies is a frequent use case for partner APIs.

A company that gives its partners access to data or capabilities might generate additional income streams. At the same time, it can keep track of how the exposed digital assets are being utilized, ensuring that third-party solutions that use their APIs deliver a good user experience and guarantee that corporate identity is maintained in their apps.

Public APIs

These APIs are also known as developer-facing or external APIs, as they are open to all third-party developers. When correctly implemented, a public API program may increase brand recognition while also providing an extra source of revenue.

APIs by Use Cases

We can classify the APIs based on the design of the system and for cases in which they are designed as:

Database APIs

Database APIs allow an application to communicate with a database management system. Developers work with databases by creating queries to get information, modify tables, and so on. Users may construct unified queries for multiple proprietary and open-source databases using the Drupal 7 Database API, for example (Oracle, MongoDB, PostgreSQL, MySQL, CouchDB, and MSSQL).

Operating Systems APIs

These are the APIs that define how a system uses services and resources of an OS. Every OS has a set of individual APIs, such as Windows API or Linux API (kernel–user-space API and kernel internal API).

Remote APIs

Remote APIs establish interaction standards for programs that operate on different machines. Each software product accesses resources not present on the machine that is requesting them, which explains the term. Because two remote apps are connected over a communications network, primarily the internet, most remote APIs are developed using web standards.

Web APIs

This is the most popular API class. Web APIs allow the transfer of machine-readable data and functionality across web-based systems that follow a client-server architecture. These APIs mostly use Hypertext Transfer Protocol to transmit requests from web applications and answers from servers (HTTP).

API integration in software development

Why Do Modern Sites Use APIs?

Here are some of the basic reasons why a modern site uses APIs.

For Security

When websites employ APIs, their security is improved. You are not immediately connected to a server when you submit a request. You provide tiny quantities of data to the API, which is sent to the server. This reduces the risks for a data breach or unauthorized access to a server's backend.

For Speed

Without APIs, you would have to contact a store and ask them to look at all of their suppliers' inventory, which they would ultimately return to you. This, rather than having an API that allowed you to quickly see what a product was and its price.

For Scalability

APIs give scalability and flexibility to the system by leveraging data needs. You can grow your online store or service catalog without using new code each time.

Challenges of Producing APIs and Consuming APIs

These are the biggest challenges in producing APIs.

Lack of Time

Depending on what you want APIs to accomplish or how you use them, building and using APIs can be a time-consuming endeavor.

Lack of Documentation

API documentation refers to the information API providers offer to API consumers to assist them in understanding how to utilize APIs.

Lack of Knowledge

Some individuals working with APIs require more advanced technical knowledge, while others are technically competent but lack understanding of certain API capabilities.

Lack of people

challenges of producing APIs and consuming APIs like e.g. lack of people

A scarcity of people is linked to a scarcity of time and knowledge. Many teams find it difficult to create and consume APIs with their current team infrastructure. They require more personnel to extend their technical knowledge base and increase their time to devote to API initiatives.


While the notion of APIs is simple, their execution may be exceedingly difficult—many people who use and create APIs consider complexity a major roadblock.

Stakeholder Prioritization

Stakeholders, or those with a "stake" in projects and activities, are frequently in charge of allocating resources, personnel, and finances to projects. API initiatives that stakeholders do not prioritize can be a barrier for both consumers and producers.

Stakeholder Expectation

We just talked about stakeholders or a "stake" in projects and initiatives. These stakeholders frequently lack technical skills and are unclear about what they're attempting to accomplish using APIs, or worse, are too optimistic about what it will take!

Leadership buy-in

Working on something that the organization's leadership believes in, or "buy-in" to, may be extremely difficult for teams. Projects aren't prioritized and fall by the wayside when executives don't believe in APIs.

Lack of Tools

Few engineers start coding with a blank notebook. However, because not every developer has access to the tools they require, it creates a barrier.

Team buy-in

Similar to leadership buy-in, it may be difficult to take initiatives ahead if the teams creating and utilizing APIs don't believe in the project, making progress difficult, if not impossible.

API Specifications/Protocols

XML-RPC is a protocol that transfers data using a particular XML format, whereas SOAP utilizes a proprietary XML format. XML-RPC is older than SOAP, but it is considerably simpler and lighter in terms of bandwidth use.

SOAP (Simple Object Access Protocol) is an XML-based API protocol that allows users to send and receive data over SMTP and HTTP. Due to SOAP APIs, it's simpler to communicate data between apps or software components that operate in various settings or are built in different languages.

REST (Representational State Transfer) is a collection of web API architecture concepts; no formal standards exist (unlike those with a protocol). The interface must comply with specific architectural restrictions to be a REST API (also known as a RESTful API). Although RESTful APIs can be built using SOAP protocols, the two standards are typically considered competitors.

gRPC is an open-source global API framework that falls within the RPC umbrella. Unlike SOAP, RPC is a considerably younger protocol, having been introduced by Google in 2015. gRPC allows a client program to call methods from a server application on another machine as a local object. This facilitates the development of distributed services and applications.

GraphQL is an API query language. It enables the client to specify the precise data it requires and simplifies data aggregation from various sources. It allows the developer to make only one API call to obtain all of the information required. Another unique aspect of GraphQL is that it describes data using a type system.

Amazing examples of APIs

API usage examples and application programming interface

Here are some examples:

Google Maps

The Google Maps APIs are used by the vast majority of websites that include a map. Google's Directions API, for example, returns XML or JSON-formatted directions between geolocations via an HTTP request.


Vulkan is a platform-independent API that operates at the operating system level. It allows developers to produce high-quality, real-time visuals in apps and controls communication between the program and the graphics processing unit. If you're interested, look at the Vulkan API docs.

Skyscanner Flight Search is a metasearch engine that allows travelers to search Skyscanner's database of pricing for the cheapest airline deals. Skyscanner also provides a RESTful API to its affiliate partners that support both XML and JSON as data exchange formats. They urge partners to make requests using just the HTTPS protocol to increase security. Their documentation can be found here.


WeatherAPI this is a free geolocation and weather information service with various APIs that include weather forecasts, IP lookups, sports, astronomy, geolocation, and time zone information. It uses a JSON/XML RESTful API to offer access to geodata and weather. To use the API, developers can use either HTTP or HTTPS. They give thorough documentation on how to use all of their APIs to developers.

Sabre Air Availability

This Sabre Air Availability SOAP API allows you to look for flights and get availability information for certain dates, origins, and destinations. It utilizes XML as the data exchange format and HTTP or HTTPS as the request protocol because it is a SOAP API.

Yelp API

This GraphQL API gives users suggestions and ratings for the finest restaurants, events, nightlife, and other things. To get data from the servers, it employs the HTTP request technique. The API uses endpoints to connect to data sources, which developers can use in their projects. The data is exchanged in JSON format.

Everyday Examples of APIs

These are some examples of day-to-day life to explain APIs' role in modern technology.

Daily Banking Transactions

Consider yourself to be a user and a bank teller to be an API. "I'd want $1,000 from this account", you say to the teller (API). The teller (API) then asks the bank manager (the system) for $1,000, which the bank manager (the system) then gives to the teller (API), who then gives it to you. As you can see, the API serves as a conduit between you and the system.

Searching for Hotels

You submit this request to such travel sites when you go into a travel site and input data like Atlanta, two nights, one room. The API sends your request for that exact location, date range, and room to ten sites, which then respond with the bargains they've discovered. You examine the ten offers and select the best one. Once again, the API serves as a conduit for your queries.

Finding a Facebook profile

Typing a name on the Facebook search bar to find out a person's profile is another everyday example of using an API.

Finding a new Restaurant

Let's pretend you are visiting a new city or country and need to find a restaurant. You can quickly locate local restaurants, their business hours, reviews, phone numbers, and directions using Google Maps API.

The Modern API

Modern APIs, on the other hand, have developed several properties that make them extremely valuable and useful:

  • Modern APIs follow developer-friendly, easily accessible, and widely understood protocols (usually HTTP and REST).
  • They are regarded as products rather than codes. They are created for consumption for certain audiences (e.g., mobile developers), documented, and adapted to allow users to expect certain maintenance and lifetime expectations.
  • As they are considerably more standardized, they have greater discipline in terms of security and governance, performance and scalability monitoring, and management.
  • As with any other software produced in the field, the contemporary API also has its development and versioning software lifecycle (SDLC). Modern APIs for consumption and versioning are well documented.

The Future of APIs

the future of api in innovative digital world

When a company creates new goods, services, business models, or processes, it uses open innovation instead of relying solely on internal expertise, sources, and resources.

As we previously stated, certain Open Innovation concepts come from this, such as Open Banking, which is one of the greatest instances of establishing an open API ecosystem driven by fintech.

And that's where open APIs come in: they are at the heart of the banking industry's revolution. Through the establishment of a common database, the Open Banking solution promises to transform the financial system.

The strategy is gaining traction in the market, bolstering the concept of an open financial ecosystem and diving headfirst into the industry's API-fiction trend. The forecast is that open platform banking services, public APIs, and outsourced applications will give the cards in the segment.


By making technology more accessible, programmers and developers are encouraged to establish an application ecosystem based on its API.

And the more individuals who utilize this API, the more opportunities for a new business will arise.

This appears to be the way things will go in the future. From now on, open APIs will play a much larger role. Do you want to learn more about APIs and how to establish one for your company? Give Selleo's top development team a shot. For additional information, please contact us.

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