Rest API Interview Questions and Answers For Experienced2024

What We Are Learn:

Rest API Interview Questions: Rest API (Representational State Transfer Application Programming Interface) is a widely used architectural style for designing web services that communicate over the internet. Rest APIs allow software applications to interact with each other using standard HTTP methods such as GET, POST, PUT, DELETE, etc.

As Rest API has become an integral part of modern web development, it’s essential to have a solid understanding of Rest API concepts, principles, and best practices. During an interview, hiring managers may ask several Rest API interview questions to assess the candidate’s expertise and experience in Rest API development.

Post On:	Rest API Interview Questions
Post Type:	Interview Questions
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Rest API interview questions can range from basic concepts such as HTTP methods, status codes, and headers to more advanced topics like security, performance optimization, and API design principles. Being well-prepared for Rest API interview questions can help you showcase your expertise and land your desired job in the field of software development. This article will provide a list of common Rest API interview questions and their answers to help you prepare and increase your chances of success.

Rest Assured API Testing Interview Questions

What is API?
What is API testing?
What are the types of API testing?
What are the protocols used in API Testing?
What are the tools used for API Testing?
What is API test environment?
What is API framework?
What are the limits of API usage?
What are the advantages of API testing?
What are the principles of an API test design?
What is API framework?
What are the common tests that performed on API?
What exactly needs to verify in API testing?
What are the differences between API and Web Services?
What is API documentation?
What is the most used template for API documentation?
What are the types of bug that can be found during API testing?
What are the difference between API testing and UI testing?
What is SOAP?
What is REST API?
What are the differences between SOAP and REST API?
What are the major challenges faced during API testing?
What are the difference between API Testing and Unit Testing?
What is a RESTFUL web services?
What is Resource in REST?
What is the way to represent the resource in REST?
What protocol is used by the RESTFUL Web Services?
What are the characteristics of REST?
What is messaging in RESTFUL Web Services?
What are the components of an HTTP request?
What is the HTTP protocol supported by REST?
Can we use GET request instead of PUT to create a resource?
What is URI? What is the purpose of web-based service and what is it’s format?
What are SOAP Web Services?
When we can use SOAP API
What is the difference between JSON and JSON Schema? (Mphasis)
Difference between Path and Query Parameters with an example
How to send a GET request using Rest Assured?
How to log response in Rest Assured only in the case of an error.
Explain different ways of extracting a single field from a response body.[like using response, JSONPath,XMLPath] and also they will give you the response of a request and ask you to extract the response of a particular field.
How to mask header information in API testing using Rest Assured?
How to download a file using rest assured?
How do you handle form parameters and multipart parameters[uploading media file]?
They will give you an end to end scenario and ask how will you write the rest assured code for that [ they are trying to understand how well can you do the API chaining here , you can just explain also]
What import statement will you use for Rest Assured to work?
How to check that a specific item is present in a collection using Rest Assured?[we can use Matchers here]
What are the common exceptions you encounter in Rest Assured?
Explain the rest Assured framework you wrote in your previous org?
How do you handle data in Rest Assured? [POJO, Excel,config file,HashMaps]
What is the use of ResponseSpecification in Rest Assured?
How do you handle authentication and authorization in Rest Assured tests?[basic, oauth,digest,custom]
What are the common pitfalls or challenges you have faced while using Rest Assured, and how did you overcome them?
What is the difference between given(), when(), and then() methods in Rest Assured and explain with an example.
How do you handle cookies in Rest Assured tests?
How can you handle timeouts and retries in Rest Assured tests?
Reporting in Rest Assured.
How do you enable parallel execution of Rest Assured tests? [TestNG,XML]
How do you verify the status code of an HTTP response using Rest Assured?
How do you handle dynamic status codes or scenarios where the status code may change between test runs?
How can you handle dynamic data or parameters in Rest Assured requests?
How to handle ssl certificates in rest assured.
What is API automation testing? How does it differ from UI automation testing?
What are the advantages of API automation testing?
How do you select the appropriate tools and frameworks for API automation testing?
Explain the steps involved in testing an API.
What are the commonly used HTTP methods in API testing?
What is the difference between GET and POST methods in API testing?
How do you handle authentication and authorization in API automation testing?
What is JSON? How do you parse and validate JSON responses in API automation testing?
What is the role of assertions in API automation testing?
How do you handle dynamic data in API responses during automation?
What is endpoint testing, and how do you perform it?
How do you handle error responses and status codes in API automation testing?
What are some common challenges faced in API automation testing, and how do you overcome them?

What is the difference between the patch and put method in RestApi?
When we use the get method, data is not secured, and when we use it to post, this method hides data.
What is Authentication?
Why do we use mocks or stubs?
What is the difference between rest API and microservices?
Why do we get parameter session and variable declaration in API?
What are the main methods that we use for API automation?
What are the JSON converters headers of API?
Once the response comes, what actually do we get?
How to create API?
How does caching work in microservices?
What is REST ASSURED?
Explain mocking.
What expectations does the Technical panel see for the tester from an API Automation perspective?
Why do we do API Testing what is the advantage and where we can do API testing?
Can anybody explain POJO
What are web services and APIs, and what are their differences?
What are the Authenticated techniques/Types? can we use them to access the rest of the API?
What are the different ways to pass authentication in API requests?
Difference between PUTS and POST in API.
What is the global variable in Postman?
Environment variable in postman.
Difference between put and patch.
What is the 409 response code?
How to pass JSON file to a payload
Pass payload using a hashmap.
Write a program to take a get request using rest assured, and from the response, verify if data is present in the database using SQL.
What is OUTH, and why does the company use it nowadays?
What is API automation testing? How does it differ from Ul automation testing?
What are the advantages of API automation testing?
How do you select the appropriate tools and frameworks for API automation testing?
Explain the steps involved in testing an API.
What are the commonly used HTTP methods in API testing?
What is the difference between GET and POST methods in API testing?
How do you handle authentication and authorization in API automation testing?
What is JSON? How do you parse and validate JSON responses in API automation testing?
What is the role of assertions in API automation testing?
How do you handle dynamic data in API responses during automation?
What is endpoint testing, and how do you perform it?
How do you handle error responses and status codes in API automation testing?
What are some common challenges faced in API automation testing, and how do you overcome them
Describe the process of testing GraphQL APIs and compare it to testing RESTful APIs.
Explain the concept of rate limiting in APIs and how you would test for it.
Discuss the challenges and strategies for testing APIs that involve complex authentication mechanisms like OAuth 2.0.
Explain how you would handle testing for APIs that involve file uploads or downloads.
Discuss strategies for handling versioning in APIs and how you would test backward compatibility.
Describe the process of API testing in a microservices architecture. How does it differ from testing monolithic APIs?
Explain the concept of API contract testing and its significance in modern software development.
How would you approach testing for performance and load handling of APIs? Mention specific tools or techniques you’d use.
Explain the differences between mocking and stubbing in API testing, and when would you use each approach?
Describe the strategies you’d employ for testing APIs that are constantly evolving or changing

Rest API Interview Questions

Rest API interview questions assess a candidate’s knowledge and experience in designing and developing Rest APIs, covering HTTP methods, security, performance optimization, and API design principles. Preparing for these questions is crucial for candidates looking to succeed in software development job interviews.

What are Web services?
What is the difference between SOAP and REST
What is REST API
What is the difference between Web services testing and API testing
Difference between XML and HTML
What is Assertion
Types of Assertions
Difference between Xpath and XQuery
Types of Properties and their syntaxes
What is Data-Driven Testing
What is the Data Source Test step
Explain about JDBC process
How to Connect JDBC to SOAP UI
What is Connection String in JDBC
Difference between SOAP UI FREE v/s SOAP UI PRO
What are Data Sink and Data gen test steps in SoapUI pro
How to Transfer value using Property Transfer
What are Mock services
How to do Service mocking
What is the process of SOAP UI Testing
What is WSDL
What are the parameters are in WSDL
Explore the WSDL
Is WSDL necessary for SOAP UI?
Difference between HTTP and HTTPS
Why HTTP is important in Webservices
What is an Endpoint?
What are the HTTP methods and HTTP Status Codes?
Explain different types of HTTP methods and Usage
Explain different Status codes
Types of HTTP Status codes
What is the Request Header ? and its format?
What is Response Header ? and Its format?
What tools are available for SOAP testing
Do you have experience in Load Testing
How to test Load Testing
What are TPS, Response Time, and Breakeven point
Absolute vs. Relative Xpath?
What are Name Space and its usage
How to write Xpath for access attributes?
SOAP UI Architecture
How to generate Reports in the Free Version
Why API Testing?
Is there any difference between SOAP and REST API testing? If so, how?
Key things you test in an API let’s say a GET API to fetch a list of 5 records with id and name
GET vs POST
POST vs PUT vs PATCH example for each
What do you mean when you say PUT is idempotent? Conditions for idempotency?
Do you follow any strategy for sending large payloads in POST.
Is it a good idea to have assertions for request headers when testing apis?
How do you get a request header in Rest-Assured?
If I send a text file as an input in a POST call, what will be the content-type?
Key things to test when you API response feeds into a down stream system?
URI vs URL with a simple example.
Can you explain more about the JWT format and how it works for authentication in an API?
Do you know if caching is applied in the rest api’s that you test? How do you test caching in api’s
How do you test expired or invalid tokens in your API’s?
How do you test user roles and permissions in your API, tell us some of the best practices that you follow for testing such user permissions in API’s.
Have you heard of the term rate-limiting? Can you explain when should we use rate limiting in API’s
Do you generate reports of the api tests that you run? What are some key attributes to include in the report.
Have you heard of the term api gateway? What does it do?
What is the difference in path param and query params?
Do we need to use POJO class and serialisation in RestAssured, when we can directly send request body in the form of String?
Can I use cookies with rest assured if so how can I set a cookie for a domain?
Do you know what is a HEAD request? Can you think of a scenario when HEAD request would be needed.
Is POST a cacheable method? Is PUT a cacheable method?
Difference between api virtualisation and mocking?
What is JSON Schema? Can I use same json schema for validating the response of two different api’s?
What is API caching and in how many ways can we cache api response

Interview Questions on Rest API

Different HTTP methods
HTTP status codes ( 200/400/500 series)
Put/post/patch
401 vs. 403
Query and path parameters
How to construct JSON requests (POJO/JSON Object/JSON Arrays)
How to validate Response ( POJO / JSON path /object Mapper)
How to validate/test API(different cases )
What are Authorization or API keys
RestAssured code snippets or HTTP client code snippets
Is API Testing, part of functional or non functional testing?
What is API Gatekeeper
Can we use Boundary value analysis or EP techniques or error guessing techniques to test APIs
As a QA/SDET, do we involve in API Documentation?
Does API has any relationship with Serverless
What is the difference between RestAPI and Restful
Can we access API with CLI
Difference between API and Library
HTTP API vs RestAPI
Is it possible to test an API using Browser DevTools or Browser extensions…
Can Rest API use HTTPS protocol
How do you fetch data globally in API Automation
Can we Automate all the APIs
What do you understand by RESTful Web Services?
What is a REST Resource?
What is URI?
What are the features of RESTful Web Services?
What is the concept of statelessness in REST?
What do you understand by JAX-RS?
What are HTTP Status codes?
What are the HTTP Methods?
Can you tell the disadvantages of RESTful web services?
Define Messaging in terms of RESTful web services.
Differentiate between SOAP and REST?
While creating URI for web services, what are the best practices that needs to be followed?
What are the best practices to develop RESTful web services?
What are Idempotent methods? How is it relevant in RESTful web services domain?
What are the differences between REST and AJAX?
Can you tell what constitutes the core components of HTTP Request?
What constitutes the core components of HTTP Response?
Define Addressing in terms of RESTful Web Services.
What are the differences between PUT and POST in REST?
What makes REST services to be easily scalable?
Based on what factors, you can decide which type of web services you need to use SOAP or REST?
We can develop webservices using web sockets as well as REST. What are the differences between these two?
Can we implement transport layer security (TLS) in REST?
Should we make the resources thread safe explicitly if they are made to share across multiple clients?
What is Payload in terms of RESTful web services?
Is it possible to send payload in the GET and DELETE methods?
How can you test RESTful Web Services?
What is the maximum payload size that can be sent in POST methods?
How does HTTP Basic Authentication work?
What is the difference between idempotent and safe HTTP methods?
What are the key features provided by JAX-RS API in Java EE?
Define RESTful Root Resource Classes in the JAX-RS API?
What do you understand by request method designator annotations?
How can the JAX-RS applications be configured?
Is it possible to make asynchronous requests in JAX-RS?
List the key annotations that are present in the JAX-RS API?
Define RestTemplate in Spring.
What is the use of @RequestMapping?
What are the differences between the annotations @Controller and @RestController?
What does the annotation @PathVariable do?
Is it necessary to keep Spring MVC in the classpath for developing RESTful web services?
Define HttpMessageConverter in terms of Spring REST

Rest Assured API Testing Interview Questions

Difference between REST and SOAPUI.
The method in REST.
Difference between PUT and PATCH call
How to integrate postman into the project?
How will you handle dynamic payloads in API?
How do you capture specific response values and pass them to other requests?
What challenges did you face in API testing?
What is the difference between Authorization and Authentication?
What are the API status codes you have come across?
What is the difference between OAuth1.0 and OAuth2.O? When and where do you use and how. Can you write a sample code?
How do you get the response from one API and send it to another API?

Rest Assured Automation Interview Questions

What is Rest?
What tools are avail for REST?
What is JSON?
What is URI?
What is “R” in URI?
What are Params/Parameters?
What is HTTP?
Tell me a few HTTP methods and Status Codes.
What is the process for validating response data?
What Is the JSON path?
What is Header data?
What is an Authorization token?
What is the payload?
Steps to test REST application?
What is the usage of collections in POSTMAN?
What is WADL?
POST vs PUT

Rest API Testing Interview Questions

How will you handle server issues in API testing both in postman and, rest assured.. like 5xx.. explain
What is an API?
What’s the diff between Rest vs SOAP
What are the different HTTP methods?
What are the different status codes, and when will they occur?
What are the different ways you validate XML responses?
What are the different ways you validate the rest of the API response?
How do you use POJO? Sample POJO code for a JSON
How do you pass payload to rest API calls during automation?
Explain your automation framework.
Explain the challenges that you face during the automation of the rest APIs
What are the diff types of testing you do with an API
What is the diff between regular calls vs OAuth calls?
How do you test security testing using APIs
How do you do performance testing with APIs
What is the difference between Put vs Patch?
We have 200 APIs, and for all 200 APIs, there are seven fields..how you will validate. What will be your approach?
There are 25 fields you need to validate from the API response. What will be your approach? How will you validate? Will you create 25 variables to store responses for every field?
There are 1000 API post-request calls to create records. The best approach is to make our test cases run in any chrome version, irrespective of the chrome driver version.

Rest Assured Interview Questions

What is the RAML? What is the use?
How to handle dynamic bearer token authentication (token has changed every hour)
How do you know if your URL and query parameters, and path parameters are working or not
Where does use is given and when and then in your framework?
How to create a post request with dynamic data in your framework
Explain your framework
Rest and sop difference?
What does mean by rest is light compared to soap
Why soap is more secure than rest.
Different response code
When we get a stale element exception.
Explain overloading and overriding with examples.
Explain all the oops concepts you used in your framework.
If you cannot find any element, what techniques will you apply?
Verification and validation of different examples.
Response time in rest and soap services. Is any difference?

Rest Assured API Testing Interview Questions

Error code for authentication and Authorization
Whats authentication
What is the difference between put and patch requests?
Is there any way to verify the response on UI? It was asked in an interview after performing API testing how do you verify on UI.
How to debug/read/rewrite req/response of API over HTTPS using Charles?
What is the difference between oath 1 and oath 2?
Enlist some common tests that are performed on APIs?
How to identify oath 1 and oath 2?
What is the purpose of the oath?
Oath generation testing
When to use the post method
What patch method and when to use it
What are other tools for API testing, apart from postman
What all to think/consider for switching Automations framework
The internal and external API token
Generate Access token
What have mainly used HTTP methods other than post get put and delete
What have mainly used HTTP methods other than post get put and delete
How does basic Authorization work?
Explain in brief the different types of output observed of an API.
Can booleans parameterized
What all testing you will perform on an API
Whats SQL injection, how to do it
Explain in brief the different types of output observed of an API. – JSON, XML, HTML, text
Schema validation
Heartbeat call and logistics call
Https local map for Charles proxy

Rest Assured Interview Questions And Answers

What will you check first when a lot of failures in API automation?
What will you do when the API structure changes?
Which dependency is good to handle Json operations?
How do you keep Json requests in the automation framework?
Which of the following takes more time to script. Get or Post a call?
Tell me your approach to automating an API that is under development
Tell me a complex scenario you automated so far
What will be your action, when a mandatory header which is passed in all the services becomes optional?

Restassured Interview Questions

What is the difference between API and WebService?
What is the difference between SOAP & Rest API?
Can you write a sample of API(URL) and JSON?
How do you handle the Authentication token?
How many types of Authentication are in POSTMAN/ Rest-Assured.
What is the difference between OAuth1.0 and OAuth2.O, When and where do you use and how? Can you write a sample code?
What is the base URI in RestAssured?
Can you explain RequestSpecification request = RestAssured.given();
What will be returned type of response.jsonPath().getJsonObject(“XYZ”);
How do you extract the values of JSON and how do you validate the response.
Can you write a code for saving the response in a JSON file?
How do you validate the headers of the response?
What is the difference between Headers and Header classes?
What is difference between response.header(“xyz”) and response.headers() methods.
Can you extract all the headers from the response at run time?
What is JSONObject() , request.header(“xyz”), response.path(“lable”) , response.body().asString() , response.getBody().prettyPrint(); , RestAssured.given().queryParam(“xyz”,”abc”);
What is difference between request.get(“https//dev-mode.com/api/allcustomers”) and request.request(Method.GET,”/ allcustomers “);
What is the difference between PUT and Patch? Have you ever used and where.
What are status code(2xx ,3xx ,4xx, 5xx) in API.
How do you print your response in JSON format?
How do you post body in POST and how many ways to post.
What all are the dependencies for Rest-Assured.

Rest API Interview Questions For Experienced

How to parse a JSON
How to parse an XML
How to Insert key: value based upon some searching criteria
Write code for conversion of JSON to XML and XML to JSON
What do you mean by the query parameter and path parameter?
What is the difference between put and patch?
What is the validation while API automation?
Explain your framework(Rest Assured)
What do you mean by object notation and array notation in JSON?
Write code for JSON Read
What do you mean by POJO why do we use POJO?
What do you mean by authentication and what are the types of authentication while API testing
What is the difference between URI and URL
How do you store the result and use it further in groovy scripting
What do you mean by Test runner in groovy scripting
What is the Rest of the service architecture?
What is the soap service architecture?
What is the soap UI work hierarchy?
How to set and get property using Groovy scripting
What do you mean by jsonsluper and xmlholder
How to convert JSON to Hashmap
What do you mean by Data source Data Sink and Data Source loop and why do we use it
How to handle SSL in SoapUI
What are the different types of properties in SoapUI that you declare using Groovy scripting?
What is the main thing while API automation?
What do you mean by Webservices and why do we use Webservices.
What is the difference between soap and Rest?
What do you mean by UDDI .and what do you mean by WSDL.
What is the different type of HTTP Methods?
How to parse a list from a JSON, for example, there is JSON and there are multiple IDs how you will parse all the IDs from JSON and how you will parse a particular I’d from that JSON.

API Automation Testing Interview Questions

The model used of your Rest API means how your following rest API ( these are coming from the Richardson maturity model)
The architecture of the API project ( Jax-rs with jersey or restless etc)
How you create JSON data on post-call. ( I mean are you hardcoding data in code or somewhere you calling like JSON or CSV file)
How you extract path parameters
How do you read JSON response ( here JSON object, JSON array, reading whole key-value pair, etc)
The question will be about headers and cookies ( in Get call and post-call related)
Maintaining URLs ( means get a call or post-call or delete call URL; here interviewer will make twist based on your earlier told how your company follows API development, simply Richardson model)
Question will be from what is path parameters, query parameters, etc
Extent report or default report.
Some database query as you know API bit related to DB as just making the sure response and request was dropped in DB or not OK

Java Rest API Interview Questions

Difference between Get and Post call?
How/why do we call Get and Post a call?
Is it mandatory to send request data in JSON format only?
How does API work?
Please explain RPC API.
What is the difference between REST API and microservices?
Why we do get parameter session and variable declaration in API?
why do we use mocks or stubs?
Difference between SOAP API and REST API?
What is the difference between the patch and put method in RestApi?
What is the difference between a REST and RESTful?
What is REST ASSURED?
How does caching work in microservices?
What are the expectations the Technical panel sees for a tester from an API Automation perspective?
Why do we do API Testing what is the advantage and where we can do API testing?
What is API testing?
What is API?
How do APIs work?
What are the different types of API testing?
What protocols can be tested using API Testing?
What are the most commonly used tools for API testing?
What are the differences between API Testing and Unit Testing?
What are the advantages of API Testing?
What is the approach followed in API Testing?
What needs to be verified in API testing?
What are the best practices that need to be followed for writing test cases?
What do you understand by Black Box Testing?
Define Test Data.
Define test coverage.
Does the API tester need to have coding knowledge to perform API testing?
What is the process of API Specification Review?
What is Latency in API testing?
What do you understand by Throughput in Performance testing?
How do you document an API functionality? What are the tools available for achieving the same?
What is the most important difference between API testing and UI testing?
What are the major blockers or challenges faced while performing API testing?
What are the principles that need to be followed while performing API Testing?
What are the different bugs that can be found in API testing?
Define Test API.
What is Payload?
What is Run Scope?
What is the importance of caching mechanism?
Why is automated API testing useful?
What do you understand by Input injection?
What do you understand by the test environment for API?
Is it possible to hack API while testing?
How should we test the API security?
What do you understand by Big Bang Approach in testing?
How do you perform API Load Testing

So we request to all visitors share their experience on REST API and Rest API Interview Questions with us. If you have any queries related to this post please leave a comment and we will update you as soon as possible.

HTTP Status Codes in API Responses

Successful Response (200 OK): When you make a GET request to fetch user data, and the server successfully returns the user’s information. After successfully submitting a form, the server responds with a 200 OK status code to acknowledge the submission.

Created (201 Created): When you make a POST request to create a new resource, such as submitting a new blog post, and the server creates the resource and returns a 201 status code along with the URL to the newly created resource.

No Content (204 No Content): After successfully deleting an item, the server might respond with a 204 status code to indicate that the request was successful, but there is no data to return.

Bad Request (400 Bad Request): When you send a request with missing or invalid parameters, and the server responds with a 400 status code to indicate that the request is malformed or incorrect.

Unauthorized (401 Unauthorized): If you try to access a protected resource without providing valid authentication credentials, the server may respond with a 401 status code, indicating that authentication is required.

Forbidden (403 Forbidden): When you attempt to access a resource that you don’t have permission to access, the server may respond with a 403 status code to indicate that access is forbidden.

Not Found (404 Not Found): If you request a resource that does not exist on the server, the server will respond with a 404 status code to indicate that the requested resource was not found.

Internal Server Error (500 Internal Server Error): In case of an unexpected server-side error, like a database connection issue or unhandled exception, the server may return a 500 status code, indicating that something went wrong on the server.

Service Unavailable (503 Service Unavailable): If the server is temporarily down for maintenance or experiencing an overload, it might respond with a 503 status code to inform clients that the service is currently unavailable.

API Automation Challenges And Best Practices

Data Management:
Challenge: Managing test data for API tests can be complex, especially when dealing with various data formats.
Best Practice: Use data-driven testing approaches. Store test data separately and keep it organized. Utilize data generation tools if needed.

Dependency Management:
Challenge: APIs often rely on other APIs or services, making it challenging to control dependencies.
Best Practice: Mock or stub-dependent services to isolate the API under test. Use dependency injection or service virtualization tools.

Dynamic Data:
Challenge: APIs may return dynamic data, such as timestamps, making it difficult to write stable tests.
Best Practice: Use assertions that account for dynamic data, like using regular expressions or ignoring specific fields when comparing responses.

Authentication and Authorization:
Challenge: Testing APIs that require authentication and authorization can be complex and may involve security concerns.
Best Practice: Implement token-based authentication for testing. Ensure secure handling of authentication tokens and simulate various authorization scenarios.

Rate Limiting and Throttling:
Challenge: APIs may have rate limits or throttling mechanisms that affect the testing process.
Best Practice: Coordinate with developers to bypass rate limits during testing or implement rate-limiting strategies in your test scripts.

Error Handling:
Challenge: Properly validating error responses and handling unexpected errors can be challenging.
Best Practice: Write test cases to cover both expected error scenarios and unexpected errors. Ensure clear error messages for debugging.

Environment Setup:
Challenge: Creating consistent test environments that mimic production can be complex.
Best Practice: Use containerization tools like Docker to set up and manage test environments, ensuring consistency across different stages.

CI:
Challenge: Integrating API tests into CI/CD pipelines smoothly can be tricky.
Best Practice: Automate test execution within your CI/CD pipeline. Use tools like Jenkins, Travis CI, or GitLab CI for seamless integration.

Monitoring and Reporting:
Challenge: Monitoring and reporting test results across multiple APIs and versions can be overwhelming.
Best Practice: Implement a robust reporting system that provides clear insights into test results, failures, and trends. Use tools like TestNG, JUnit, or custom reporting solutions.

Documentation and Collaboration:
Challenge: Lack of clear API documentation or poor collaboration with development teams can hinder testing efforts.
Best Practice: Collaborate closely with developers to ensure clear API documentation. Use tools like Swagger or Postman to document and share API details.

Structural Validation of JSON Using Rest Assured

Validating the response received from the server is a vital task in API testing. Here we will see how we can perform Structural or Schema Validation of JSON response. Schema is nothing but a JSON file. It will have only datatype information & the expected keys of the JSON. There won’t be any values present in the schema. For Schema validation, we need to create a schema for our JSON. We can manually create the schema or we can use any online schema generators.

The steps we will follow are like:

Add a “JSON schema validator” dependency in pom.xml.
Add a “hamcrest-all” dependency for asserting the JSON schema.
Load the expected “schema.JSON” in a file object e.g.
File schema = new File ( System.getProperty (“user.dir”) + “schema.json” );
Fire the rest assured request, validate the response body using the ‘matchesJsonSchema’ method eg.

given (). get ( “http://localhost:8080/abc/123” ).
then (). body (matchesJsonSchema (schema ) );

The ‘matchesJsonSchema’ method validates the response body matches the structure-data type and the required keys. If there is any mismatch, it will report in the console.

Code will be like :

public class StructureValidation {
@Test
public void JSONSchemaValidation () {
File schema = new File (System. getProperty (“user.dir”) + “schema1.json” ) ;
given ().
get (“http://localhost:8080/abc/123”) .
then ().
body (matchesJsonSchema (schema) ) ;
}

Schema validation programmatically is very useful when you have a nested JSON, which is very time consuming if we need to validate manually.

What are the common HTTP Request methods?

HTTP defines a set of request methods to indicate the desired action to be performed.

GET: retrieve data.
HEAD: identical to GET request, but without the response body.
POST: submit an entity to the specified resource.
PUT: modify data with the request payload.
DELETE: delete the specified resource.
CONNECT: establish a network connection to a web server.
OPTIONS: find out the HTTP methods and other options supported.
TRACE: performs a message loop-back test.
PATCH: apply partial modifications to a resource.

What is Serialization?

Serialization: In Java, serialization is the process of converting an object into a stream of bytes in order to store the object or transmit it to external file. Its main purpose is to save the state of an object in order to be able to recreate it when needed.

What is deserialization?

Deserialization: The reverse process, which reconstructs the object from the stream of bytes, is called de serialization. To make an object serializable, the class of the object must implement the java.io. Serializable interface. This is a marker interface.

What is marker interface?

Marker Interface: In Java, a marker interface is an interface that contains no methods or fields and is used to indicate that a class implementing the interface has a certain property. Marker interfaces are also known as tag interfaces. A marker interface is typically used to provide a common base type for a group of related classes. For example, the java.io. Serializable interface is a marker interface.

What is the use of transient keyword in Java?

transient keyword: transient is a modifier which is used to prevent the particular class member to be de sterilized.

API Status Code Cheat Sheet

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Here are the some of frequently asked Rest API Interview Questions.

What is REST API?

REST API is an acronym for Representational State Transfer. REST API provides a framework for designing network applications by using HTTP requests and responses.

It helps to build reliable and secure distributed systems that scale to meet the needs of large organizations while remaining simple enough for small teams or individuals to use them effectively.

It’s an architectural style that describes how resources are manipulated in the application using URIs (Uniform Resource Identifiers) and HTTP methods such as GET, POST, PUT, DELETE, etc.

Rest API Definition?

A REST API is a web application interface that provides access to data or functionality on one computer system via the network using standard, stateless HTTP requests.

The advantage of this method is that it can be used from any programming language, with any networking library.

It also allows developers to work with APIs without knowing how they are implemented or what they do.

What are Rest API best practices?

Rest API best practices are usually described as the following:

1. Take care of authentication, including basic authentication and token-based authentication.
2. Use different HTTP methods for different requests.
3. Put performance in mind when designing your API. You may need to use caching or compression depending on your needs.
4. Make sure you implement rate-limiting appropriately to avoid any security risks.

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