Rest API Development Interview Questions

Checkout Vskills Interview questions with answers in REST API Development to prepare for your next job role. The questions are submitted by professionals to help you to prepare for the Interview.

Q.1 Explain the concept of content negotiation in REST.

Content negotiation allows clients to specify the desired representation format (e.g., JSON, XML) in the request headers.

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Q.2 What is the purpose of the OPTIONS HTTP method in REST?

The OPTIONS method is used to retrieve information about the communication options for a resource, such as supported HTTP methods.

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Q.3 How do you handle versioning of a RESTful API?

Versioning can be done by including the version in the URL (e.g., /v1/resource) or using HTTP headers.

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Q.4 What is the purpose of Cross-Origin Resource Sharing (CORS)?

CORS allows web applications to make requests to a different domain, enabling cross-origin communication.

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Q.5 How can you handle long-running operations in a REST API?

Use asynchronous processing and provide mechanisms like callbacks or polling to inform clients of completion.

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Q.6 Explain the concept of idempotent HTTP methods in REST.

Idempotent methods, such as GET, PUT, and DELETE, have the same effect whether they are called once or multiple times.

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Q.7 How do you prevent SQL injection in a REST API?

Use parameterized queries or prepared statements when interacting with a database to prevent SQL injection attacks.

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Q.8 What is the purpose of a REST API documentation tool like Swagger?

Swagger generates interactive API documentation, making it easier for developers to understand and use the API.

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Q.9 How can you implement rate limiting in a REST API?

Implement rate limiting by tracking and limiting the number of requests from a client IP address within a certain time window.

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Q.10 What is the purpose of the HEAD HTTP method in REST?

The HEAD method is used to retrieve the headers of a resource without fetching the resource's body, useful for checking resource availability.

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Q.11 How can you handle authentication for mobile app clients in a REST API?

Implement OAuth or JWT-based authentication for mobile app clients to securely access the API.

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Q.12 What is the difference between REST and GraphQL?

REST is an architectural style with fixed endpoints, while GraphQL allows clients to request exactly the data they need.

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Q.13 How do you handle data validation in a RESTful API?

Implement input validation and use appropriate HTTP status codes (e.g., 422 Unprocessable Entity) for validation errors.

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Q.14 Explain the concept of rate limiting in the context of API security.

Rate limiting limits the number of requests from an IP address to prevent abuse and protect server resources.

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Q.15 How can you handle versioning of API endpoints in a REST API?

Versioning can be achieved by including the version in the URI path or using custom request headers.

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Q.16 What is the purpose of content negotiation in RESTful APIs?

Content negotiation allows clients to request responses in different formats (e.g., JSON, XML) based on their preferences.

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Q.17 How do you implement security headers in a REST API?

Implement security headers like Content Security Policy (CSP), Strict-Transport-Security (HSTS), and X-Content-Type-Options.

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Q.18 What is the purpose of the Accept header in HTTP requests?

The Accept header specifies the media types (e.g., JSON, XML) that the client can accept in the response.

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Q.19 How do you handle versioning when the API evolves over time?

Use backward-compatible changes and communicate breaking changes clearly, possibly introducing a new version.

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Q.20 What is API throttling, and why is it used?

API throttling limits the number of requests a client can make to prevent overloading the server and ensuring fair usage.

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Q.21 How can you ensure data integrity in a REST API?

Use HTTPS to encrypt data during transit, and implement validation checks to ensure data consistency and integrity.

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Q.22 What is the purpose of content-type negotiation in RESTful APIs?

Content-type negotiation allows clients and servers to agree on the format of data exchanged in requests and responses.

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Q.23 How do you handle concurrent requests in a REST API?

Implement locking mechanisms, optimistic concurrency control, or use database transactions to handle concurrent requests.

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Q.24 Explain the concept of request/response headers in REST.

Request headers provide information about the request, while response headers provide details about the response from the server.

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Q.25 How can you handle API versioning when using microservices?

Each microservice can have its versioning strategy, allowing for independent versioning and updates of services.

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Q.26 What is the purpose of content negotiation headers in HTTP?

Content negotiation headers like Accept and Content-Type enable clients and servers to specify their preferred data format for communication.

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Q.27 How do you ensure data security in a REST API?

Use encryption (HTTPS), authentication, authorization, and input validation to protect data and prevent security vulnerabilities.

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Q.28 How can you implement request logging and monitoring in a REST API?

Implement logging frameworks and monitoring tools to track requests, errors, and performance metrics.

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Q.29 What is the purpose of the OPTIONS HTTP method in CORS preflight requests?

The OPTIONS method is used to determine which HTTP methods and headers are allowed in cross-origin requests.

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Q.30 How can you handle versioning in a REST API without breaking existing clients?

Use backward-compatible changes and provide clear documentation on deprecated features and new versions.

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Q.31 Explain the concept of content negotiation using the Accept header.

The Accept header allows clients to specify the desired media type (e.g., JSON, XML) for the response from the server.

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Q.32 What is the role of hypermedia in RESTful APIs?

Hypermedia (HATEOAS) allows clients to navigate a REST API by following links provided in responses, reducing coupling.

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Q.33 How can you implement caching strategies in a RESTful API?

Implement cache-control headers, ETags, and cache expiration policies to control caching behavior in API responses.

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Q.34 What is the purpose of the PATCH HTTP method in REST?

The PATCH method is used to apply partial modifications to a resource, updating only the specified fields.

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Q.35 How can you handle error responses in a RESTful API?

Use appropriate HTTP status codes and provide descriptive error messages in the response body to help clients understand issues.

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Q.36 What is API versioning, and why is it important?

API versioning allows you to make changes to the API while ensuring compatibility with existing clients.

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Q.37 How do you prevent SQL injection in a REST API written in PHP?

Use prepared statements or parameterized queries when interacting with a database to prevent SQL injection attacks.

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Q.38 What are the advantages of using JSON as the data format in a REST API?

JSON is lightweight, human-readable, and widely supported, making it a popular choice for data exchange in APIs.

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Q.39 How can you optimize the performance of a REST API in Java?

Optimize database queries, use caching, and implement proper indexing to improve the performance of a Java-based REST API.

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Q.40 What is the purpose of the HEAD HTTP method in RESTful APIs?

The HEAD method is used to retrieve headers of a resource without fetching its body, useful for checking resource availability and metadata.

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Q.41 How do you handle input validation and sanitation in a PHP-based REST API?

Validate and sanitize user input to prevent security vulnerabilities and data corruption.

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Q.42 What is the role of API documentation in RESTful API development?

API documentation provides clear and comprehensive information about how to use the API, helping developers understand its capabilities.

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Q.43 How can you handle authentication and authorization in a Python-based REST API?

Use libraries like Flask-Security or Django-Rest-Framework to implement authentication and authorization mechanisms.

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Q.44 What is the purpose of response pagination in a REST API?

Pagination divides large data sets into smaller chunks, improving response times and reducing data transfer in API responses.

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Q.45 How do you ensure data consistency in a REST API written in Python?

Implement transactions and proper error handling to maintain data consistency in a Python-based REST API.

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Q.46 What do you understand by RESTful Web Services?

RESTful Web Services are basically REST Architecture based Web Services. In REST Architecture everything is a resource. RESTful web services are light weight, highly scalable and maintainable and are very commonly used to create APIs for web-based applications.

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Q.47 What is a REST Resource?

REST architecture treats every content as a resource. These resources can be Text Files, Html Pages, Images, Videos or Dynamic Business Data. Resources are the basic building block of a RESTful service. Examples of a resource from an online book store application include a book, an order from a store, and a collection of users. Resources are addressable by URLs and HTTP methods can perform operations on resources.

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Q.48 What REST stands for?

REST stands for representational state transfer. A REST API (also known as RESTful API) is an application programming interface (API or web API) that conforms to the constraints of REST architectural style and allows for interaction with RESTful web services. REST stands for representational state transfer and was created by computer scientist Roy Fielding.

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Q.49 What are the REST constraints?

REST defines 6 architectural constraints which make any web service – a truly RESTful API and which are: Uniform interface, Client–server, Stateless, Cacheable, Layered system and Code on demand (optional)

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Q.50 What is URI?

Similar to URL, URI (Uniform Resource Identifier) is also a string of characters that identifies a resource on the web either by using location, name or both. It allows uniform identification of the resources. A URI is additionally grouped as a locator, a name or both which suggests it can describe a URL, URN or both.

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Q.51 What is the advantage of RESTful web services?

REST APIs provide a great deal of flexibility. Data is not tied to resources or methods, so REST can handle multiple types of calls, return different data formats and even change structurally with the correct implementation of hypermedia.

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Q.52 Differentiate between REST API vs. SOAP?

SOAP is a protocol, whereas REST is an architectural style. An API is designed to expose certain aspects of an application's business logic on a server, and SOAP uses a service interface to do this while REST uses URIs.

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Q.53 What is statelessness in REST?

As per the REST architecture, a RESTful Web Service should not keep a client state on the server. This restriction is called Statelessness. It is the responsibility of the client to pass its context to the server and then the server can store this context to process the client's further request.

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Q.54 What is caching in REST API?

Caching is the ability to store copies of frequently accessed data in several places along the request-response path. Caches along the response path can take a copy of a response, but only if the caching metadata allows them to do so.

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Q.55 What does stateful mean in REST?

Stateful means that it's holding the state on it's own (possibly in memory or local disk) that doesn't mean it can't backup the state in a database. Stateless means that it is depended only on 3rd party storage because it doesn't store any kind of state in memory.

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Q.56 What is JAX-RS?

Jakarta RESTful Web Services or JAX-RS also called earlier as Java API for RESTful Web Services, is a Jakarta EE API specification that provides support in creating web services according to the Representational State Transfer (REST) architectural pattern.

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Q.57 What are HTTP Status codes?

An HTTP status code is a message a website's server sends to the browser to indicate whether or not that request can be fulfilled. Status codes are set by the W3C and are embedded in the HTTP header of a page to tell the browser the result of its request.

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Q.58 Which HTTP method equals create, under CRUD

The POST HTTP method equals create, under CRUD

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Q.59 What does consistent resource naming conventions and URI formatting results in

Consistent resource naming conventions and URI formatting results in minimum ambiguity, maximum readability and maintainability

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Q.60 What are the HTTP Methods?

The primary or most commonly-used HTTP methods are POST, GET, PUT, PATCH, and DELETE. These methods correspond to create, read, update, and delete (or CRUD) operations, respectively.

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Q.61 List any disadvantages of RESTful web services

You can lose the ability to maintain state in REST, such as within sessions. It's important to understand what makes a REST API RESTful, and why these constraints exist before building your API.

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Q.62 What do you understand by Messaging in terms of RESTful web services.

RESTful Web Services make use of HTTP protocols as a medium of communication between client and server. A client sends a message in form of a HTTP Request and the server responds in the form of an HTTP Response. This technique is termed as Messaging.

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Q.63 What is rest message format?

A REST request is a simple HTTP request just like a regular browser would send to a web server. There is typically no XML request sent. A REST response is typically an XML document sent back in a regular HTTP response, just as if a browser had requested it.

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Q.64 What is URI in Web service?

A Uniform Resource Identifier (URI) is a generic term for the names of all resources connected to the World Wide Web. URIs enable the protocols over the internet to conduct the interactions between and among resources.

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Q.65 List best practices to develop RESTful web services

Few best practices for REST API design are: Accept and respond with JSON, Use nouns instead of verbs in endpoint paths, Name collections with plural nouns, Nesting resources for hierarchical objects, Handle errors gracefully and return standard error codes,

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Q.66 What are Idempotent methods?

An idempotent method means that the result of a successful performed request is independent of the number of times it is executed.

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Q.67 How Idempotent methods are relevant in RESTful web services domain?

Methods like GET, OPTIONS, TRACE, and HEAD are idempotent because they do not change the state of resources on the server.

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Q.68 Differentiate between REST and AJAX.

The main difference between AJAX and REST is that, Ajax is a set of technologies. It is a method to dynamically update parts of the UI without having to reload the page. REST, on the other hand, is a type of software architecture. It is a method for users to request information from servers.

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Q.69 How you keep yourself updated of new trends in REST API?

REST API and data science are seeing newer development every year and I update myself by attending industry seminars, conferences as available online or offline.

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Q.70 How do you see yourself in next five year in REST API?

I foresee a bright future as I will gain more skills and knowledge in the domain of REST API and data science by adding new technologies as needed by my organization.

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Q.71 What are your strengths as a REST API professional?

As a REST API professional I am having extensive experience in development of web services and web applications using. I also have the requisite managerial skills for managing team and achieve the assigned tasks.

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Q.72 How do you prioritize REST API development related tasks?

REST API based development involves many tasks on a day to day basis. Tasks also need to be prioritized to accomplish the organizational goals as per the specified KPIs (key performance indicators). Prioritization of tasks is done on the basis of various factors like: the tasks relevance, urgency, cost involved and resource availability.

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Q.73 How you manage your time for REST API related development?

REST API based development involves lots of tasks which need to be completed in a specific time frame. Hence time management is of utmost importance and is applied by: using to do lists, being aware of time wasters and optimizing work environment

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Q.74 Why do you want the REST API job?

I want the REST API job as I am passionate about web service development and making companies more efficient by using REST API.

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Q.75 What do you think of most important role of a REST API professional?

As a REST API development professional my focus is to provide the effective and efficient programs using REST API so as to fulfil the needs of the company.

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Q.76 What is REST, and what does it stand for?

REST stands for Representational State Transfer. It is an architectural style for designing networked applications.

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Q.77 What are the key principles of REST?

Key principles include statelessness, client-server architecture, and the use of HTTP methods for CRUD operations.

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Q.78 Explain the difference between REST and SOAP.

REST is an architectural style that uses lightweight protocols like HTTP, while SOAP is a protocol with rigid standards.

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Q.79 What is an HTTP status code, and why is it important?

HTTP status codes indicate the outcome of an HTTP request, helping clients understand the server's response.

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Q.80 What is an HTTP GET request, and when is it used?

HTTP GET is used to retrieve data from a server and should not have any side effects on the server.

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Q.81 What is an HTTP POST request, and when is it used?

HTTP POST is used to send data to a server to create a new resource, such as submitting a form.

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Q.82 What is URL encoding, and how is it used in REST?

URL encoding is used to format data in URLs, typically for parameters in HTTP requests.

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Q.83 Explain the purpose of HTTP headers in REST.

HTTP headers provide metadata and control information about an HTTP request or response.

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Q.84 What is an HTTP PUT request, and when is it used?

HTTP PUT is used to update or replace an existing resource on the server with the provided data.

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Q.85 What is an HTTP DELETE request, and when is it used?

HTTP DELETE is used to request the removal of a resource on the server.

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Q.86 What is the difference between PUT and PATCH in REST?

PUT is used to replace a resource entirely, while PATCH is used to partially update a resource.

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Q.87 What is the purpose of query parameters in a URL?

Query parameters are used to filter, sort, or modify the data returned by an API endpoint.

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Q.88 What is the request payload, and where is it used in REST?

The request payload contains data sent with an HTTP request, often in the body of a POST or PUT request.

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Q.89 Explain the concept of resource URIs in REST.

Resource URIs uniquely identify resources on the server and are used to access them via HTTP.

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Q.90 What is content negotiation in REST, and why is it important?

Content negotiation allows clients to specify the desired content format (e.g., JSON or XML) for the response.

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Q.91 What is HATEOAS, and why is it a constraint in REST?

HATEOAS (Hypertext As The Engine Of Application State) means that clients can navigate a REST API through links in responses.

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Q.92 Explain the role of HTTP methods in REST API design.

HTTP methods (GET, POST, PUT, DELETE, etc.) are used to perform CRUD operations on resources in REST APIs.

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Q.93 How does RESTful API differ from a traditional web service?

RESTful APIs adhere to REST principles, using standard HTTP methods, while traditional web services may use custom protocols.

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Q.94 What is CORS, and why is it needed in REST API development?

CORS (Cross-Origin Resource Sharing) is needed to allow requests from a different origin (domain) in web applications.

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Q.95 How do you handle versioning in a REST API?

Versioning can be done using the URL path (e.g., /v1/resource) or through HTTP headers (e.g., Accept-Version).

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Q.96 What is an API endpoint in REST, and how is it defined?

An API endpoint is a specific URL where clients can access a resource or perform an operation. It is defined by the server.

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Q.97 Explain the concept of idempotence in RESTful APIs.

An operation is idempotent if performing it multiple times has the same effect as performing it once.

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Q.98 What is the purpose of status codes like 200 and 404 in HTTP?

Status code 200 means a successful request, while 404 indicates that the requested resource was not found.

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Q.99 How can you secure a REST API against unauthorized access?

You can use authentication mechanisms like API keys, OAuth, or JWT tokens and implement proper authorization checks.

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Q.100 What is the role of the HTTP OPTIONS method in REST?

The HTTP OPTIONS method is used to retrieve information about the communication options for a resource.

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Q.101 How do you implement authentication in a REST API?

Authentication can be implemented using API keys, Basic Auth, OAuth, JWT, or other methods depending on the security requirements.

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Q.102 What is the difference between stateless and stateful communication in REST?

REST follows a stateless model, where each request from a client to the server must contain all information needed to understand and process the request.

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Q.103 How can you handle errors and exceptions in a RESTful API?

Use appropriate HTTP status codes (e.g., 400 for bad requests, 500 for server errors) and provide error details in the response body.

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Q.104 Explain the role of rate limiting in API development.

Rate limiting controls the number of API requests a client can make within a specified time frame to prevent abuse.

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Q.105 What is content-type in HTTP headers, and why is it important?

Content-type specifies the format of the data in the request or response body (e.g., JSON, XML, HTML).

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Q.106 How do you handle file uploads in a RESTful API?

Use multipart/form-data or Base64 encoding for file uploads, and specify the appropriate content type.

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Q.107 What is the purpose of pagination in API responses?

Pagination is used to limit the number of records returned in a single response, improving performance and reducing data transfer.

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Q.108 How do you implement caching in a REST API?

Use HTTP caching headers (e.g., Cache-Control) to specify how responses should be cached by clients and intermediaries.

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Q.109 What is the role of the ETag header in HTTP?

ETag (Entity Tag) is used for cache validation, allowing clients to check if a resource has changed since the last request.

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Q.110 How can you test a REST API?

Testing can be done using tools like Postman, curl, or writing automated tests using testing frameworks.

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