Table of Contents[Hide][Show]
- 1. What do you understand by REST?
- 2. What do you mean by REST API?
- 3. What exactly is URI?
- 4. What are the characteristics of RESTful Web Services?
- 5. What are the guiding principles of REST?
- 6. Mention the HTTP methods that REST supports.
- 7. Describe the restrictions placed by a consistent interface.
- 8. What exactly is a REST Resource?
- 9. What does JAX-RS mean to you?
- 10. What distinguishes AJAX and REST from one another?
- 11. Can you list some RESTful web services drawbacks?
- 12. What distinguishes PUT and POST techniques from one another?
- 13. How do you test RESTful web services?
- 14. Describe a REST API in the real world.
- 15. How does Microservice Architecture Work?
- 16. What exactly is caching?
- 17. Describe payload.
- 18. Differentiate SOAP Vs REST?
- 19. Can the transport layer security protocol (TLS) be used with REST?
- 20. Idempotent methods: what are they? How does it apply to the world of RESTful web services?
- 21. What is the functionality of HTTP Basic Authentication?
- 22. Do you think GraphQL is the best choice for creating microservice architecture?
- 23. What are the main distinctions between the safe and idempotent HTTP methods?
- 24. What does the JAX-RS API imply by RESTful Root Resource Classes?
- 25. What exactly is Postman, and why is it used?
- 26. How are REST APIs kept secure?
- Conclusion
REST’s evolution has made APIs incredibly accessible while also revealing their full strength and potential. REST APIs are easy to create and cache because of their resource-oriented architecture.
Additionally, throughout time, RESTful APIs were the forerunners of other significant developments like cloud computing and microservice-based design.
Therefore, it should come as no surprise that REST API developers are in demand today given how they provide businesses that employ RESTful services a competitive edge. REST APIs are a popular design trend.
Many IT firms want REST API knowledge from software developers and ask about it in technical interviews.
Here are some of the most typical REST API interview questions that will help you be ready for interviews at various firms if you want to work in the REST API development field.
1. What do you understand by REST?
REST is an architectural paradigm for designing web-based applications that are based on the Hypertext Transfer Protocol (HTTP).
REST defines certain standards that web services must meet to be deemed RESTful. These recommendations guarantee that requests and resources are transmitted quickly and effectively between client and server using standardized HTTP protocols.
2. What do you mean by REST API?
A software-to-software link known as an application programming interface enables communication and data sharing between otherwise independent programs. For example, a news website could use the Twitter API to discover pertinent tweets automatically and integrate them into news stories.
An API that adheres to REST principles is known as a REST API, sometimes known as a RESTful API. In a REST API, each piece of data is handled as a resource and given a distinct standard resource identity (URI).
For instance, the Twitter API makes every tweet a retrievable resource that is available to clients. The Twitter API can be used by users to post tweets and carry out other website tasks.
3. What exactly is URI?
A computer network resource can be referred to using a URI or uniform resource identifier. It serves as a means of separating one resource from another. The sources might or might not be online.
Due to their standard structure, URIs make it simple to connect to even various types of resources. The location or name of the resource is included in URIs together with a string of characters.
The URI is made up of a path, scheme, query, and other elements but does not include the protocol.
Using a protocol, URLs (Uniform Resource Locators) are used to find resources on the internet or accessible through it.
4. What are the characteristics of RESTful Web Services?
- The Client-Server paradigm is the foundation of the service.
- The service can access resources via using URIs.
- The service utilizes the HTTP Protocol to acquire data/resources, run queries, and do other tasks.
- Messaging is the name of the method used to communicate between the client and the server.
- These services can also implement the REST architectural pattern using SOAP services.
- To reduce server calls for the same sort of repetitive requests, these services also employ the idea of caching.
5. What are the guiding principles of REST?
Five criteria must be met by REST APIs:
Client-server decoupling: Only a series of requests and replies can be used to communicate between the client and server. Only clients and servers are able to send requests and answers, respectively. This straightforward idea enables both parties to function independently of one another.
Uniform Interface: There must be a uniform protocol for all client-server connections. This protocol for REST is HTTP. Because each application requests and sends data using the same language, a consistent interface makes integrations simpler.
Stateless: The server does not save any records of previous requests or answers in stateless communication. Each request and answer provide all the details required to complete the exchange. Stateless communication enhances speed, saves memory, and lessens the stress on the server. Additionally, it avoids the potential of a request failing due to incomplete data.
Layered system: Servers that reside between the client and the API server are referred to as layers. These extra servers perform a variety of services, such as detecting spam and optimizing speed. Layers in REST are modular, meaning they can be added and deleted without impacting communications between the client and the API server.
Cacheable: Clients can cache any resources to boost speed if server answers indicate whether or not the resource is cacheable.
On-demand coding: In response, an API can transmit executable computer code to customers. The client application can then run the code on its own back end.
6. Mention the HTTP methods that REST supports.
The HTTP methods that REST supports are:
- GET: This method asks for a resource at the specified URL. A request body shouldn’t be included because it will be ignored. It could be possible to cache it locally or on the server.
- POST: This method sends data to a service for processing, and the service should normally return a new or changed resource.
- PUT: The resource is updated at the request URL.
- DELETE: The resource is deleted at the request URL.
- Options: It identifies the supported methods.
- HEAD: The request URL’s metadata is returned.
7. Describe the restrictions placed by a consistent interface.
In order to separate the client from the server, a consistent interface is required.
To achieve a consistent interface, the following four constraints are required:
- Resource identification: Client requests must utilize standard resource IDs to identify resources (URIs)
- Resource manipulation using these representations: Clients have all the information required to be able to change resource state when they get a resource representation from the server.
- Self-descriptive messages: Messages include all metadata and other information required for the receiver to understand them.
- Hypermedia as the application state engine: The channel for client-server communication is hypermedia, such as HTML, and clients don’t need API-specific documentation to comprehend server answers.
8. What exactly is a REST Resource?
Resources are the fundamental components of a RESTful web service in a REST architecture. They include all crucial information that an API client needs to access.
Any type of resources, such as an HTML page, an image, a video, or anything else needed for an API activity, can be accessed through the server in a client-server system.
The resources are identified by a Uniform Resource Identifier. Text, JSON, or XML are all acceptable representations of resources. Having stated that, there are no limitations on the representation’s format.
9. What does JAX-RS mean to you?
It is simpler to create RESTful web services in Java thanks to the Java API for RESTful web Services, often known as JAX-RS. Developers can describe resources and the operations that can be carried out on them using the annotations that are provided.
10. What distinguishes AJAX and REST from one another?
Ajax:
- Ajax is a group of technologies that allows for the dynamic updating of user interface elements without having to reload the page.
- Ajax removes asynchronous communication between the client and server.
REST:
- REST demands communication between the server and the client.
- The utilization of resources is important to the URL structure and request/response pattern used by REST.
11. Can you list some RESTful web services drawbacks?
Sessions cannot be kept up since the services adhere to the notion of statelessness. (The client is responsible for passing the session id throughout the simulation of the session.)
Security constraints are not fundamental to REST. The protocols that use it inherit the security precautions. Therefore, taking caution while putting security measures in place, such as integrating SSL/TLS-based authentications, is important.
12. What distinguishes PUT and POST techniques from one another?
PUT:
- There is no cache for PUT responses.
- Idempotent (i.e. multiple requests will yield the same result)
- the request’s payload updates or replaces the target resource.
POST:
- idempotent not (i.e., multiple requests will yield multiples of the same resource)
- The web server processes the payload of the request based on the intended resource.
- If the appropriate cache-control header is included, POST replies can be cached.
13. How do you test RESTful web services?
RESTful web service testing can be aided by a number of tools, including Swagger and Postman. Inspecting request parameters like query parameters, headers, and response headers is made possible by the latter’s abundance of features.
Postman can be used to make requests to endpoints and show the results. And XML and JSON can be created from these answers.
Postman and Swagger both provide extremely comparable functionalities. On the other hand, Swagger also offers capabilities like endpoint documentation.
14. Describe a REST API in the real world.
- Travel and ticketing websites can leverage the flight timings and pricing that airlines make available through APIs.
- In order for mapping and navigation apps (like Google Maps) to use them, public transportation agencies often make their data publicly available in real-time via APIs.
- Weather applications use open APIs that exchange weather data to display weather information.
- Developers can access Google Maps’ mapping data via a number of its hosted APIs. These APIs are used by developers to embed dynamic maps in their apps and websites.
15. How does Microservice Architecture Work?
- Requests are sent by various customers using various devices.
- After confirming the clients’ identities, identity providers provide security tokens.
- The client requests are managed by API Gateway.
- All of the system’s material is preserved as static content.
- The management tool checks the balance of services on nodes and any faults.
- Discovering the path of communication between microservices is aided by service discovery.
- Data centers and proxy servers make up dispersed network systems called content delivery networks.
- Remote services provide information access from a distance.
16. What exactly is caching?
The practice of temporarily keeping a copy of a server answer somewhere (such as computer memory) in order to access it later more rapidly is known as caching.
Caching enhances server speed when using REST APIs by decreasing the amount of work the server must do to satisfy the request. Applications that utilize the API run quicker thanks to caching because they don’t have to submit a new request each time they need a resource.
The HTTP response header’s Cache-Control field contains information about how long a resource can be cached by the client before it needs to be accessed again.
17. Describe payload.
The payload in REST refers to the information contained in the body of the HTTP response. The customer used the GET technique to request the data in question.
The document containing the tweet text and any necessary files for putting the tweet on a website will be included in the payload, for instance, if you ask the Twitter API for a specific tweet. Additionally, the payload can be included in the HTTP request using the POST method.
18. Differentiate SOAP Vs REST?
- Unlike SOAP, which can only handle XML, REST enables a wider range of resource formats, including XML, text, HTML, pictures, video, and more.
- When security is crucial for online applications, SOAP is helpful. REST cannot be utilized when transactions must be completed securely since it is not particularly secure.
- Since SOAP is only a protocol, REST can use it in its web services but not the other way around.
- While REST is only an architectural pattern used to develop web services and abides by certain limitations such as client-server setup, statelessness, cacheable response, layered systems, and consistent interface, SOAP is a protocol that operates on particular standards that must be rigorously adhered to.
- While REST uses universal resource identifiers (URIs), SOAP uses service interfaces to provide its capabilities to client applications. REST has a lower bandwidth need than SOAP since SOAP messages are more information-heavy.
19. Can the transport layer security protocol (TLS) be used with REST?
In fact, we can. The REST client and server’s communication is encrypted via TLS, and the protocol also gives clients a way to authenticate servers.
Due to the fact that it is the Secure Socket Layer’s replacement, it is utilized for secure communication (SSL). Implementing RESTful web services is successful with HTTPS because it cooperates effectively with both TLS and SSL.
The REST inherits the characteristics of the protocol it implements, which is one thing to note here. As a result, security protections are reliant on the protocol that REST uses.
20. Idempotent methods: what are they? How does it apply to the world of RESTful web services?
When the URI is the same, some HTTP methods in a request have the same impact on the server whether they are delivered once or several times. Idempotent techniques are what these are known as.
For instance, no matter how many times a URI using the GET method is run, the server will always experience the same result. Idempotent methods include GET, PUT, and PATCH, to name a few.
Idempotent HTTP methods are some of the ones utilized by RESTful web applications. They are necessary to guarantee consistency in the RESTful web services’ activities.
Customers that use REST APIs can make code errors that force a REST API to make accidentally repeated requests. These calls have the potential to misuse resources.
21. What is the functionality of HTTP Basic Authentication?
When using Basic Authentication as part of APIs, the user must submit the username and password, which are concatenated by the browser in the form “username: password” and base64 encoded.
On every HTTP request from the browser, the encoded value is delivered as the value for the “Authorization” header. Because the credentials are just encoded, it is recommended to use this form when sending HTTPS requests because they are not secure and can be intercepted by anybody if security protocols are not utilized.
22. Do you think GraphQL is the best choice for creating microservice architecture?
Microservices and GraphQL go along perfectly because GraphQL keeps your microservice architecture a secret from your clients.
From the front end, you want all your data to come from a single API, while from the back end, you want to divide it into microservices. The best technique I’m aware of to achieve both is by using GraphQL.
It enables you to divide your backend into microservices while still giving each application a single API and enabling joins across data from various services.
23. What are the main distinctions between the safe and idempotent HTTP methods?
Idempotent methods produce the same result when invoked once or several times through the same request. The PUT method is idempotent.
All safe ways are idempotent, but not all idempotent methods are safe since safe methods do not alter the resources. For instance, GET is secure since it just retrieves data and does not alter the resource.
Additionally, it is idempotent, meaning that it will always return the same answer when invoked.
24. What does the JAX-RS API imply by RESTful Root Resource Classes?
The Java Enterprise Edition provides classes and interfaces that adhere to the JAX-RS API requirements. With the aid of JAX-RS, creating Java web services in the REST architectural style is made easier.
In the JAX-RS API, root resource classes are just “plain old java objects,” or POJO. In order to implement the necessary web resources, they employ JAX-RS annotations.
They either have @path annotations or at least one of their methods has @path annotations. They can be summed up as Java classes with methods for dealing with API endpoints.
25. What exactly is Postman, and why is it used?
An API development tool called Postman is used to create, test, and modify APIs. This tool can be used by developers for whatever feature they require for an API. It simplifies and facilitates developers’ work.
Postman makes it easy to make a variety of HTTP queries, including GET, POST, PUT, and PATCH, save environments for later use, and convert APIs to code in a number of different languages.
Each stage of the API cycle is made simpler with Postman, and cooperation is streamlined for quicker API development.
Additionally, it enables developers to manage the documentation, specifications, test cases, processes, and API catalogs.
26. How are REST APIs kept secure?
Since REST APIs don’t use as rigorous security safeguards as SOAP APIs, sensitive data shouldn’t be sent or retrieved using them.
However, trustworthy REST APIs continue to integrate security controls for safe and dependable data transmissions.
- Authentication and authorization: Each and every request made to the API must pass these two checks. Verifying the client’s identity through authentication and validating that they have authority to access the requested resources through authorization are two different processes.
- Validation: Before the API grants access to its resources, requests must still be checked for possibly harmful code after authentication and authorization. A server would thus be open to an injection attack.
- Validation: Before the API grants access to its resources, requests must still be checked for possibly harmful code after authentication and authorization. A server would thus be open to an injection attack.
- Encryption: TLS/SSL encryption protects the connection between the client and server and keeps hackers from intercepting requests and answers.
- Rate-limiting techniques, such as limits and throttling, protect servers from brute-force assaults like DDoS that aim to degrade or crash them.
- No sensitive information in URIs: Resources’ URIs shouldn’t contain any protected data (such as a user name, password, or authentication token).
Conclusion
Congratulations! Several basic to complex REST API interview questions and their respective solutions are now at your fingertips.
Now that you have a good concept of how to respond to some of the typical REST API interview questions, you can go on to respond to the interviews. The next step depends on your objectives.
Visit Interview Series with Hashdork to prepare for interviews.
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