Everything You Should Know About APIs

API stands for Application Programming Interface. An API is a connector/ intermediary between two software components. It is a set of definite protocols that makes the interface possible. The interface simply means the nature of requests and responses. How developers would form the request and responses comes under API documentation.

In simpler words, API allows two applications to communicate with each other. We use API when we check the weather on our phones or while sending and receiving messages on apps like Instagram or Facebook, etc.

Cycle of API

When we use an application on our device, here’s what happens:

Request or data is sent to the server – server interprets and understands the request – it provides the needful response – the response is successfully sent back to the device.

Each time we demand a particular response from the application, this cycle repeats.

Different API Protocols and Architectures:

  • REST: Among the multitude of API architectural types, REST (representational state transfer) is highly preferred and adopted. No data or status is stored by REST API. REST API works upon the concept of relying on a client/server approach that bifurcates the front and back ends of APIs.
  • SOAP: SOAP (Simple Object Access Protocol) is widely used to create web APIs with XML. It is compatible with numerous communication protocols on the internet like HTTP, TCP, and SMTP. Since SOAP is easily extensible, it is easy to add features and write them vividly. Some distinct features of SOAP, as compared to other architectures, are highly structured, tightly controlled, and clearly defined standards.
  • RPC: RPC (remote procedural call) is capable of invoking executable actions. It is ideal for sending various parameters and receiving responses accordingly.

Types of API

API can be categorized into different types, depending on their usage. Other factors that help us to differentiate various kinds of API are the level of access and the scope of use.

A company must choose the right kind of API as per their requirements.


Under this API, the access to data is only limited to the authorized clients who have official licenses. Only those who have a business relationship with the company providing the API can work with its API.

Partner APIs are favored majorly by organizations because they have a say in how those resources are used. Along with that, they get greater control over who can access these resources.

Benefits of Partner APIs:

  • More focus can be given to the core strengths and developments of the company rather than the developer(s) working on it. What one developer might find hard to tackle can be easily solved by another. Thus, this collaboration is highly beneficial for the project.
  • Retaining Partner API policies help in integrating numerous eCommerce software solutions, making the software up-to-date and relevant in this fast-changing industry.

B. Public APIs

As the name signifies, a Public API is all open and available to be used by any outside developer or business. Public API is ideal for those business structures that believe in sharing their applications and data with the public and other business organizations as well.

Benefits of Public APIs:

One of the prime benefits of Public API is that it can be used anywhere if a user has internet connectivity. Apart from that, public APIs are easy to implement.

C. Internal API

An internal or private API can only be accessed by the enterprise to connect data within the business. Internal APIs have relatively weak security and authentication, which can be a reason for threat to the data. That is why the arrangement of security is gradually changing.

Benefits of Internal APIs:

One of the main advantages of Internal APIs is that it enables the developers to formulate and build new and relevant apps in a shorter amount of time. As Internal API connects the contrasting parts of the business, adaptation and flexibility become easier in the development process.

D. Composite API

Composite API is nothing but a hybrid of two or more APIs, integrating the best features of everything. They bring in higher speed, flexibility, and better performance resulting in improvements.

Benefits of Composite APIs:

Why Composite API is preferred over other APIs is the ability to perform multiple operations in a single callout. Rather than parsing various responses, the necessary data is at the end of the sequence.

How API Works

Each API is implemented by function calls whose task is to request the software to perform particular actions and functions. When a user initiates an API call, then it informs the application to perform a task. Then application uses an API to communicate with the web server and perform tasks.

Basically, API acts as a bridge between application and web server. So, every time a user instructs to software to perform any task or request any information, then the results will come through APIs. There are many relatable examples of API that we use in our everyday lives, such as Facebook login, PayPal payments, weather snippets on google, etc.

What Are Function Calls?

These are phrases that include nouns and verbs. They are also described in the API documentation.

The task of API is to simplify and speed up software development.

Some Tools for API Development

  • Sandbox: It is an easy mock RESTful API that majorly reduces cost, which is associated with third-party API calling during testing.
  • Apigee: When any company is facilitating data transfer between apps and services, Apigee by Google comes a handful. It is an ideal tool for building connected apps.
  • APIMatic: For website APIs, APIMatic is a developer experience platform. It is highly flexible for maintaining API updates.

It also enables the developers to convert API descriptions into multiple formats such as WADL, Swagger, RAML, OAI format, IO Docs, API Blueprint, HAR 1.4, Postman Collections, etc.

Practices for Building API

The top 5 building practices from API are as follows:

1. Security: A great way to build a safe and secure API is using token-based authentication. When considering safety, user-friendliness shouldn’t be compromised.

2. Documentation: A nicely-curated API decreases the project cost and enhances efficiency and implementation time. Extensive documentation of the API should be created, which enables other mobile app developers to understand the entire process in detail.

3. Throttling: App throttling is the best thing you all should consider when it comes to redirecting the overflow of traffic, safeguarding from DoS (Denial of Service), and backup APIs.

4. SDK and Libraries: Sped-up development is possible by offering needful resources to the development team.

5. Overriding HTTP Method: Employing the custom HTTP Header X-HTTP-Method-Override, allows RESTful API to override the HTTP method because there are some proxies that only support POST and GET methods.

Some Facts About API

  • The use of API has increased by 13x since 2007
  • Google, Facebook, and Twitter get around 5-10billion calls all because of API
  • Netflix’s API allows it to stream over 200 devices

Java, Python, Node.js, PHP, and ASP.Net web development, APIs are involved in every technology. API has paved the way from easy and top-notch software development to business collaborations. It accelerates the profits of companies by building a safe environment for digital and technological connectivity. It can be modified and built just as per your business requirements. APIs are discreet and get all the real work done in the application.


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