Application Programming Interface (API) simplifies the process of integrating various applications by providing readily available codes and information pipelines to assist developers in building robust digital solutions. API acts as a mediator among applications to streamline the interaction with one other. However, due to diverse applications architectures, API can be of different types like Program, Local, Web, or REST API.  

This article explains API and REST API differences. It briefly describes the types and protocols of API along with the benefits of REST API.


  • Understanding of HTTP and Web Services.

Introduction to API

Application Programming Interface, abbreviated as API, enables connection between computers or computer programs. It is a Software Interface that offers services to other software to enhance the required functionalities. Over the past few years, API has gained popularity in the market for almost every web application. For instance, each time you check the weather or book a travel ticket on your smartphone, an API is called at the backend.

As API enables businesses to open their applications’ data and functionality to external third-party developers, it eventually grows business partnerships, driving more revenue.

You can also check our article on steps to integrate SQL server REST API.

Types of API

Based on their uses and application, API can primarily be of three types:

1) Web API

Web API is an Open-Source Interface that can be easily accessed using the HTTP Protocol, generally called an API over the web. It leverages a large number of client entities, like Smartphones, Tablets, or Laptops. A Web API can be developed using various technologies like Java and ASP.NET, providing superior performance and faster service development. However, as Web APIs are designed for distributed services, they are lightweight and have limitations in bandwidth.

2) Local API

Local APIs are OS or middleware services offered to an application program. For instance, Microsoft’s .NET APIs, the TAPI (telephony API), and database access APIs are forms of Local APIs.

3) Program API

Program APIs are based on Remote Procedure Call (RPC) technology that makes a remote program component appear local to the rest of the software. One such program API is the service-oriented architecture API of Microsoft’s WS-series.

API Protocols & Architecture

Based on the purpose, an API follows a range of protocols and standards. Below are a few essential API protocols and architecture:


The XML-RPC protocol was created by Dave Winer to exchange information between two or more networks. The client performs RPC by using XML to encode its calls and HTTP requests for data transfer.


The JSON-RPC is a lightweight RPC encoded in JSON, similar to XML-RPC, which allows notifications and multiple calls to the server, which may be asynchronously answered.

3) SOAP(Simple Object Access Protocol)

SOAP is an established Web API protocol for exchanging structured information. It uses XML to Authenticate, Authorize, and Communicate processes running on operating systems. Since web protocols like HTTP run on most operating systems, SOAP allows clients to invoke web services and receive responses irrespective of language and platform.


Representational State Transfer (REST) is an architectural style to provide standards between systems on the web. REST is neither a protocol, nor library, nor a tool, so communication between systems becomes easy. REST architecture makes the implementation of Client and Server independent without affecting the operation of the other.

Understanding the Need for API

Given below are some of the reasons why APIs are used within organizations:

1) Automation

Automation accelerates API testing, thereby increasing efficiency. Not only does API glues the digital world with its dynamic nature, but it also allows companies to become more agile by automating workflows.

2) Integration

Integration of platforms and applications can be done using API to leverage seamless communication. Without APIs, enterprises lacked connectivity, which proportionally reduced productivity and performance. Integrating systems allows the movement of data, facilitating companies to automate workflows and improve workplace collaboration.

3) Efficiency

Efficiency increases with decreasing human intervention. Providing API access prevents duplication of content, offering greater flexibility for companies to spend time in quality innovation.

4) Security

Security is an additional benefit because API supplements an extra layer of protection between your data and server. However, developers can strengthen their security by using tokens, signatures, and transport layer security (TLS) encryption.

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Introduction to REST API

REST API is an API that follows a set of rules for an application and services to communicate with each other. As it is constrained to REST architecture, REST API is referred to as RESTful API. REST APIs provide a way of accessing web services in a flexible way without massive processing capabilities. Below are the underlying rules of REST API:

1) Statelessness

Systems aligning with the REST paradigm are bound to become stateless. For Client-Server communication, stateless constraint enforces servers to remain unaware of the client state and vice-versa. A constraint is applied by using resources instead of commands, and they are nouns of the web that describe any object, document, or thing to store/send to other resources.

2) Cacheable

Cache helps servers to mitigate some constraints of statelessness. It is a critical factor that has improved the performance of modern web applications. Caching not only enhances the performance on the client-side but also scales significant results on the server-side. A well-established cache mechanism would drastically reduce the average response time of your server.

3) Decoupled

REST is a distributed approach, where client and server applications are decoupled from each other. Irrespective of where the requests are initiated, the only information the client application knows is the Uniform Resource Identifier (URI) of the requested resource. A server application should pass requested data via HTTP but should not try modifying the client application.

4) Layered

A Layered system makes a REST architecture scalable. With RESTful architecture, Client and Server applications are decoupled, so the calls and responses of REST APIs go through different layers. As REST API is layered, it should be designed such that neither Client nor Server identifies its communication with end applications or an intermediary.

Key Benefits of REST API

1) Flexible

REST API is flexible with multiple types of calls like return different data formats and change structurally with the correct implementation of hypermedia. It allows users to communicate back and forth with clients and servers, even if they are hosted on different servers.

2) Adaptable

REST API is adaptable to any modification done in data that resides in the database, even when hosted on the different back- and front-end servers. Since it depends to a certain extent on codes, it helps synchronize data within websites without any issue.

3) Ease of Understanding

Flow of Data using REST APIs
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As REST uses HTTP verbs (GET, POST, PUT or DELETE) methods for communication, these methods are self-explanatory. In addition, REST architecture helps increase developers’ productivity, allowing them to display the information on the client-side and store or manipulate the data on the server-side.

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API vs REST API: Key Differences

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Although there is no direct comparison of API vs REST API, below are some parameters that can help you choose the better API:

1) API vs REST API: Structure

While structurally, most of the APIs follow the application-application format, REST API strictly operates on the web concept of Client and Server. The Client and Server are separated from one another, giving more flexibility.

2) API vs REST API: Design

Generally, APIs are lightweight architectures that are designed for gadgets constrained to devices like smartphones. In contrast, REST APIs communicate over systems, making it a complex architecture.

3) API vs REST API: Protocol

The primary goal of API is to standardize data exchange between web services. Depending on the type of API, the choice of protocol changes. On the other hand, REST API is an architectural style for building web services that interact via an HTTP protocol. Although REST API was formulated in 2000 by computer scientist Roy Fielding, it remains the gold standard for public APIs.

4) API vs REST API: Support

Most of the API are easy to implement as they do not face statelessness. In contrast, REST API gets executed even if users do not know the function names and the parameters in a specific order.

5) API vs REST API: Uniform Interface

Not many API decouples the client from a server or one application from another. REST API adheres to the principles of a uniform interface and forbids the use of self or multiple interfaces within an API. Hypermedia connections should ideally be used to distribute a single interface. It should also ensure that a similar piece of data (for example, a user’s name or email address) belongs to only one uniform resource identifier (URI). As a result, regardless of the initial request, all API requests for the same resources should look the same.

6) API vs REST API: Scalability

While scalability is an issue for general APIs, REST API has a layered structure, making REST API modular and more flexible to achieve scalability.


API is a bigger umbrella, and REST API is a unique type of API prevalent among mobile and cloud applications. No API is void of disadvantages, but new developers find REST API difficult because it fails to maintain the state within sessions. As modern APIs have emerged as a product that adheres to specified standards and specific audiences, businesses have improved their user interfaces quickly.

This article introduced you to APIs, its need and benefits. It also gave you a deeper understanding of the topic API vs REST API. Extracting complex data from a diverse set of data sources such as REST APIs can be a challenging task and this is where Hevo saves the day!

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Amit Kulkarni
Technical Content Writer, Hevo Data

Amit Kulkarni specializes in creating informative and engaging content on data science, leveraging his problem-solving and analytical thinking skills. He excels in delivering AI and automation solutions, developing generative chatbots, and providing data-driven AI & ML solutions. Amit holds a Master's degree and a Bachelor's degree in Electrical Engineering, consistently achieving distinction in his studies.

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