A Comprehensive Guide You Must  Know all About RESTful API

Restful API is simple, organized, and predictable, like following a recipe. It's like the glue that helps different computer systems work together smoothly, allowing apps and websites to share and use data in a clear and efficient way.

In this IT world, technological advancement has immensely improved and created a positive impact globally. Furthermore, you must have used the Climate App once in a lifetime and efficiently gotten the real-time weather information of any state or country while sitting in one corner of the world. Isn’t it amazing? How is this magic happening? The sole answer to this question is better communication. But does man communicate with machines? Or a machine communicates with another machine, and if yes, then how do they communicate with each other? What is their language of communication?

Hold on, hold on, and have some patience. In this blog post, you will find answers to all your questions. So, without keeping you much awaited, let’s roll-and-roll!

The Climate app uses an API to display real-time weather information on your device. Oh Gosh! Another question arises: what is API? Join our Java classes in Pune and take the first step towards becoming a skilled Java developer!

Know everything about API (Application Programming Interface)

To talk or provide important information one machine uses an API (application programming interface).  In simple words, it is a bridge between clients (the user makes a request) and web services (the user gives responses). Through APIs, software developers (primarily experienced) are able to efficiently build application software.

Now we are exploring the types of APIs that exist in the IT universe.

Types of APIs

There are various kinds of  APIs which are widely used. Some of the most popular APIs are enlisted below for better understanding:

Open APIs:

As the name suggests, open APIs are APIs that are freely available to all. Developers are easily able to access the Open API. To access the Open API, one can register. Many of the businesses out there in the IT-business world use the Open API and enhance it as per their requirements and needs.

Partner APIs:

Partner APIs are a kind of API that are utilized by businesses to offer services. Through partner APIs, the respective businesses enhance the functionality and create new and creative features within their applications to boost productivity. It also helps businesses elevate the customer experience, leading to immense growth in their revenue.

Internal APIs:

As the name says, the internal APIs are meant to access data within the organization. What does this mean? Through internal APIs, organizations fetch sensitive data that they never want to disclose; furthermore, developers rarely opt out of internal APIs to make user interfaces. Internal APIs are mainly created to bridge components in microservices.

Composite API:

Composite means mixture. Composite APIs consist of many APIs that are beautifully used by developers to meet their goals. By using composite APIs, it becomes much easier for developers to interact with highly complicated applications. Composite APIs provide the best and most cost-effective API solutions to access multiple APIs.

As we have explored different types of APIs, now we are going to explore different kinds of API protocols. Let’s move ahead and read a lot more about the two most widely used and acknowledged API protocols listed below:

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  • RESTful API: RESTful API, i.e., Representational State Transfer, is a web-based communication protocol that uses standard HTTP methods for data exchange, following principles of statelessness, resource-based URLs, and client-server interaction. In REST, API development is processed using several methods, like HTTP and JSON.

  • SOAP API: SOAP API, i.e., Simple Object Access Protocol, is a protocol that is used for interchanging structured information using XML-based messaging for communication between software applications. The SOAP API uses XML methods for sending data. Look no further than Java training in Pune

Inception of the Representational State Transfer (RESTful) API

Before exploring the REST API, let’s first understand the history of the API. Back in 1999, APIs were free for all. At that time, software developers had to use SOAP (Simple Object Access Protocol) to integrate the APIs. But SOAP APIs were tough to build and debug. Understanding the importance of APIs and experiencing all these issues, an American computer scientist named Roy Fielding introduced a brand new REST API (Representational State Transfer) at the University of California, Irvine.

Software developers who are meant to develop APIs can develop APIs through many methods. Furthermore, APIs that strongly follow the framework of REST are known as RESTful APIs.

Principles of RESTful APIs:

RESTful APIs follow several principles. Go through the below shared principles of REST architecture styles for better understanding:

  • Stateless: Under the stateless principles, request from client to the server must store full information to complete the request.
  • HTTP Methods such as GET, POST, PUT, and DELETE are widely considered to perform various operations.
  • Uniform Resource Identifiers (URIs): APIs are designed around specific, consistent URLs to access and manipulate resources.
  • Representation: Resources can have multiple representations (e.g., JSON, XML), and the client can specify the desired representation.
  • Separation of Concerns: The REST API is distinct between client and server concerns, and by doing so, it boosts the development of components.

List the HTTP requests made in the RESTful API:

There are many HTTP requests that are heavily used in the RESTful API. Some methods are discussed here:

The GET method is one of the most popular RESTful API methods that sends a request to the server, and then the server returns the result from the resource at the browser.

1. POST: POST is another HTTP method, widely used to transfer information. The method submits the data so that it can be processed by a particular resource. One of the key advantages of using the POST method is that it does not get stored in the browser (not cached).

2. PUT : The PUT method is one of the other significant HTTP methods used to update the data of the resource. It is amazing to know that in case the server does not match the request, it creates a new resource.

3. DELETE: As the name implies, the DELETE method is used to delete or remove a particular resource that is required to be deleted or removed.

4. PATCH: This HTTP method is mainly used to perform partial changes to existing resources. Somewhat, it is basically a set of instructions that tells how to perform modification on a resource.

Note: A resource is basically a target or data set that is fetched using various HTTP methods.

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Busting the workings of the RESTful API

Let’s talk about the workings of the RESTful API.

Nowadays, in the era of technological advancement, everyone is using the Internet to get valuable information, either in the form of TEXT, IMAGE, AUDIO and VIDEO. But what’s the relation of RESTful API with this statement?

The RESTful API functions in the same way as the BROWSER. In simple words, an end user makes a request to the SERVER via API and after receiving the request the SERVER returns the response/result to the browser (Chrome, Mozilla Firefox/Microsoft Edge).

Moving ahead and breaking down the working of RESTful APIs in several steps:

1. Resource Definition and Identification (URI/URL):

Defining a unique Uniform Resource Identifier (URI), usually represented as a URL, is the first step involved in the working of the RESTful API.


Following methods are used to perform following actions on the resources:

  • GET: Used to fetch the data.
  • POST: Used to create new data.
  • PUT: Used to update existing data.
  • DELETE: Used to eliminate data from the server.

3. Stateless Communication:

RESTful APIs are stateless, which means that the server should contain all the necessary data to process the request made by the end-user.

4. Response Format (JSON, XML, etc.):

The API returns responses often in JSON or XML format that include status codes, headers, and the requested resource representation. Learn the Java j2ee skills from masters at Java J2EE Training in Pune

What are the salient features of a RESTful API?

The REST architecture’s guiding principles and limitations are followed by RESTful (Representational State Transfer) web services. Here are the most important functionalities of RESTful web services:

1. Statelessness: Under the statelessness property of REST, each request made by a client to a server must include all the data required to comprehend the end-user’s request.

2. Client-Server Architecture: Under the Client-Server Architecture, the system has been categorized into two parts: client and server.  These two parts are completely different and does not depend on each other. This provides the facility for separate development and scalability.

3. Uniform Interface: RESTful APIs offer a standardized interface that defines how clients and servers are connected.  It has mainly four  constraints, enlisted below:

. Resources are defined via URI.
. Resources are controlled by the client and server exchanging representations (e.g., JSON, XML).
.The messages shared between the client and server should be self-explanatory, so that the end user has sufficient information to understand and process the message.
. A hyperlink is provided for reference or as a guide so that the end user moves to the next application state.

4. Resource-Based: Resources are the key abstractions in a RESTful API that are identified by a unique URI and controlled by several HTTP methods like: GET, POST,PUT, and DELETE  to perform actions.

5. Representation: Resources have formats like: JSON,XML,L etc. These formats are widely used by the client to process the resources.

6. HTTP Methods: Some HTTP methods are used by RESTful web services to manipulate resources. Some HHTP methods are:
GET: Used to fetch representation of a resource.
POST: Used to create a new resource.
PUT: Used to Update pre-available resources.
DELETE: Used to eliminate a resource.
PATCH: Used to partially refurbish a resource.

7. URI (Uniform Resource Identifier): Resources are identified using unique URIs. Through URIs, clients easily locate and interact with them.

8. Idempotent Operations: The HTTP methods like PUT and DELETE are idempotent. This means that when making the same requests , clients get the same response or effect as a single request. This feature is acknowledged as one of the most reliable and safe for the system.

9. Caching: To boost the performance and reduce the server load, responses should be defined as being cached or not.

10. Layered System: To elevate security and performance, intermediaries (e.g., proxies, load balancers) should be placed between : Client and Server .Enroll now for Java Framework training in Pune and boost your programming skills with experts.

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What are RESTful APIs used for?

In contemporary software development, a representational state transfer (REST) API is a specific type of web service that meets the following purposes:

1. Data Retrieval and Access:

The RESTful APIs enable the application to interact with data stored on the server. Also, through the APIs, the apps are able to access the stored data. This is a use case where clients make a request to gain results.

2. Integration Between Systems:

RESTful APIs allow integration between different systems or applications. It offers a powerful way for software components to communicate and interchange data, despite the platforms.

3. Cross-Platform Communication:

RESTful APIs facilitate communication between applications running on different devices or operating systems. This shows cross-platform compatibility and interoperability.

4. Webhooks:

RESTful APIs are used to implement webhooks, through which the application gets to receive real-time notifications from external systems (in case of an event).

5. Authentication and Authorization:

To handle both authentication and authorization, RESTful APIs come into the frame. It provides secure access to resources and protects sensitive data.

6. Web and mobile applications:

Web and mobile applications use RESTful APIs so that apps and systems communicate with server-side components and dig out all the important data.

7. Third-Party Integrations:

Applications are integrated with third-party services using RESTful APIs.. This allows for the exceptional utilization of external functionalities and information and data.

8. IoT (Internet of Things) Connectivity and Integration:

RESTful APIs are integrated with IOT applications and through the devices gets able to easily communicate with each other. Through the IOT, devices can be easily controlled, monitored, and used to interchange data more efficiently.

9. Automation and bots:

RESTful APIs enable automation of tasks and processes by allowing software to communicate with several systems.

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Pros and cons of the RESTful API:

Pros of RESTful APIs:

1. Ease of Use:

RESTful APIs are designed with an intuitive structure, make them easy to understand for API developers. Some of the HTTP methods used here are: GET, POST, PUT, DELETE, and based on a stateless client-server model.

2. Scalability:

RESTful APIs are highly scalable due to their stateless nature, as the API requests from a client to the server and moves ahead with the process, displaying the result on the client’s device.

3. Flexibility and Versatility:

RESTful APIs handles various formats of data such as  JSON, XML, etc. Thus, this significant feature enables easy integration with various applications.

4. Interoperability:

Interoperability across various hardware, software, and programming languages is made possible by RESTful APIs. Following the same REST principles, devices or apps interact with each other seamlessly.

5. Caching and Performance:

The caching mechanism is strongly supported by the RESTful APIs. This boosts performance by enabling quick responses that are cached. Through caching, repeated requests are no longer required to get the same kind of data. This eliminates the overload and also increases the speed. Join Core Java training in Pune and gain expertise in this powerful programming language.

Cons of RESTful APIs:

1. Over/Under-fetching of data:

Sometimes, when making a request, RESTful APIs provide more than enough data or less data, which leads to unnecessary data transfers and potential performance issues.

2. Limited Standardization:

Due to limited or defined principles, different APIs may behave differently. This would result in challenges in standardization and have an effect on interoperability as well as integration.

3. Complexity for Complex Operations:

In complicated processes, multiple transactions can be a daunting task. Implementing such operations might require loads of API calls and might hamper performance and efficiency.

4. Security Concerns:

Threats like data breaches or injection attacks can be faced if proper security actions such as authentication or encryption are not carried out.

5. Lack of real-time communication:

RESTful APIs strongly work on the request-result framework. This model is considered less effective for real-time systems or apps. The applications are meant to get continuous interaction as well as updates.

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Why is RESTful in the talks among the API developers?

Restful API is popular because it’s like a universal language for computers. Imagine it’s a menu in a restaurant. It organizes things neatly, making it easy for computers to understand and talk to each other. It’s like ordering food—you know what to ask for, and the restaurant knows how to give it to you. Restful API is simple, organized, and predictable, like following a recipe. It’s like the glue that helps different computer systems work together smoothly, allowing apps and websites to share and use data in a clear and efficient way. To know more visit 3RI Technologies.

Frequently Asked Questions

1. What is REST?

Ans: The full form of  REST is REST is Representational State Transfer.

2. Define what an application programming interface (API) is.

Ans: An API is the bridge through which two applications or devices communicate with each other.

3. List the types of APIs.

Ans: There are commonly four types of APIs, which are listed below:

  • Private API
  • Public API
  • Partner API
  • Composite API

4. What is the REST API?

Ans: A REST API can be defined as an API that strongly follows the REST architecture. In the REST API, data is considered a resource, and each and every resource is denoted by a URI (Uniform Resource Indicator). Also, the REST APIs share important data or information in several formats, like JSON, XML, or even plain text.

5. Explain the stateless property of REST.

Ans: Stateless is one of the important properties of the REST API and acts as one of the significant principles of REST architecture. Being stateless means that the API does not support or keep information about previous transactions of data or communications. The client and server are aware of one another’s situations, to put it simply. Every request is considered a new request, and as a result, the server provides a response.

6. List out  the advantages of the REST API?

Ans: The REST API has a list of advantages; share them below:

  • Simplicity: RESTful APIs are designed with an intuitive structure that helps developers learn it quickly.
  • Scalability: RESTful APIs are highly scalable due to their stateless nature, as the client sends an API request to the server and the server provides a response.
  • Flexibility and Versatility: RESTful APIs handle various data formats such as JSON, XML, etc.
  • Interoperability: RESTful APIs enable interoperability between different apps so that they interact with each other seamlessly.
  • Caching and Performance: The caching mechanism boosts performance through caching, as the repeated requests provide the response quickly, reducing the loading time.

7. Which protocol is mainly used while using the REST API?

Ans: HHTP i.e., Hyper Text Transfer Protocol, is mainly used by REST APIs. By using HTTP, the RESTful APIs get quickly deployed on the Internet.

8. List all the HTTP methods used in RESTful APIs to make requests or get responses.

The list of all the HTTP methods used in RESTful APIs is:

  • GET: Retrieve a representation of a resource.
  • POST: make a new resource.
  • PUT: Update pre-available resources.
  • DELETE: Eliminate a resource.
  • PATCH: Partially refurbish a resource.

9. What is CRUD in APIs? Explain.

Ans: CRUD that is Create, Read, Update, and Delete, all these four operations are very similar to operations performed on the databases using the REST APIs.

  • Create is similar to “POST”.
  • Read is similar to “GET.”
  • Update is similar to “PUT.”
  • Delete is similar to “DELETE.

10. List all the HTTP response status codes obtained from the REST API.

Answer: Some HTTP codes often obtained while working with REST APIs are listed below:

  • 200 OK: Request successful.
  • 201 Created: The request was successful and created.
  • 400 Bad Request: The request made failed because of lost data.
  • 401 Unauthorized: Request failed as the client is not authorized.
  • 403 Forbidden: Request failed as the client is authenticated but not authorized.
  • 404 Not Found: This error arises when the server failed to locate the resource.
  • 502 Bad Gateway: failed request because of invalid response.
  • 503 Service Unavailable: request failed due to maintenance or overloading

11. What is Simple Object Access Protocol?

Ans: Simple Object Access Protocol  i.e. SOAP is a protocol for interchanging structured forms of data. Also, SOAP defines a set of rules for structuring data to be shared using HTTP or SMTP. SOAP messages are a little bit complicated as compared with RESTful, which offers high security and reliability.

12. What is caching? How is it helpful?

Ans: Caching is one of the important features of RESTful APIs. It is a process or method by which a response is stored in a device or computer memory for a limited period of time (temporary). Caching is very helpful, as it speeds up the load speed when making the same request and displays the response quickly. Also, it elevates performance by reducing the server load.

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