REST Assured Interview Questions with answers, code examples, and API testing concepts
BlogsRest assured

Top 20 REST Assured Interview Questions (Basic to Intermediate)

By Ajit Marathe
9 Min Read
0

REST Assured Interview Questions are one of the most important topics for QA automation engineers preparing for API testing roles. REST Assured Interview Questions are frequently asked in interviews for SDET, Test Lead, and Automation Architect positions because they validate both conceptual understanding and hands-on coding skills. In this guide, we cover the top REST Assured Interview Questions with clear explanations, practical code examples, and interview-focused takeaways to help you crack your next interview with confidence.

In this REST Assured Interview Questions (1–20) – Basic to Intermediate, I have tried to give Clear Explanations, Code Examples & Practical Interview Takeaways.

API automation is a core expectation for any QA Automation Engineer, Test Lead, or SDET role. Among all tools available in the Java ecosystem, REST Assured stands out due to its simplicity, readability, and powerful validation capabilities.

However, most candidates fail not because they don’t know REST Assured — but because they cannot explain concepts clearly with real examples.

This guide is designed to fix that.

Each question below is structured into:

  • Clear explanation (5–6 lines, no fluff)
  • Practical code snippet
  • Real interview takeaway

Why REST Assured Interview Questions Matter in Automation Interviews?

REST Assured Interview Questions are designed to test both conceptual understanding and hands-on experience in API automation. These REST Assured Interview Questions help interviewers evaluate how candidates handle request building, response validation, and framework design. Preparing these REST Assured Interview Questions thoroughly increases your chances of cracking automation interviews.

Following are the REST Assured Interview Questions with Code Examples:

🔹 1. What is REST Assured and why is it used in API testing?

📖 Description

REST Assured is a Java-based library used for testing RESTful APIs. It simplifies HTTP request creation, response validation, and data extraction using a fluent, readable syntax. Instead of writing complex low-level HTTP code, testers can use REST Assured to write concise and maintainable test scripts. It supports JSON and XML parsing out of the box. It integrates easily with frameworks like TestNG and JUnit. Junit used to reduces effort and improves automation efficiency.

💻 Code Snippet

given()
.when()
    .get("https://reqres.in/api/users/2")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • Java library for REST API testing
  • Fluent and readable syntax
  • Reduces boilerplate code
  • Supports JSON/XML validation
  • Easy integration with frameworks

🔹 2. What are the main features of REST Assured?

📖 Description

REST Assured provides a BDD-style syntax that improves readability and aligns with test scenarios. It supports validation of status codes, headers, and response bodies using built-in methods. JSON and XML parsing are handled seamlessly through JsonPath and XmlPath. It offers request/response logging for debugging. It also supports authentication mechanisms like OAuth and Basic Auth. Additionally, it integrates well with CI/CD pipelines and reporting tools.

💻 Code Snippet

given()
    .header("Content-Type", "application/json")
.when()
    .get("/users")
.then()
    .body("size()", greaterThan(0));

🎯 Interview Takeaway

  • BDD syntax (Given-When-Then)
  • Built-in validation support
  • JSON/XML parsing
  • Authentication handling
  • Logging and debugging

🔹 3. How do you send a GET request using REST Assured?

📖 Description

A GET request is used to retrieve data from a server without modifying it. In REST Assured, GET requests are executed using the get() method within the when() block. You can add headers, query parameters, or authentication before executing the request. It is the most commonly used HTTP method in API testing. The response can then be validated using status codes and body assertions.

💻 Code Snippet

given()
.when()
    .get("https://reqres.in/api/users")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • Uses .get() method
  • Retrieves data from server
  • No request body required
  • Supports headers and params

🔹 4. How do you validate response status code in REST Assured?

📖 Description

Validating the response status code ensures that the API behaves as expected. REST Assured provides the statusCode() method in the then() block for validation. This is a fundamental assertion in API testing. Common status codes include 200 (OK), 201 (Created), 400 (Bad Request), and 404 (Not Found). Without status validation, test reliability is compromised. It is usually the first check in any API test.

💻 Code Snippet

given()
.when()
    .get("/users/2")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • Use .statusCode()
  • Validates API success/failure
  • Essential for every test
  • Covers multiple HTTP codes

Status code validation is one of the most basic checks asked in REST Assured Interview Questions.

🔹 5. What is the difference between given(), when(), and then()?

📖 Description

REST Assured follows the BDD (Behavior Driven Development) structure for writing tests. The given() block is used to define preconditions like headers, parameters, and request body. The when() block is used to perform the API action such as GET or POST. The then() block is used for validations like status code and response body. This separation improves readability and maintainability. It also aligns well with business-readable test scenarios.

💻 Code Snippet

given()
    .header("Authorization", "Bearer token")
.when()
    .get("/users")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • given() → setup
  • when() → action
  • then() → validation
  • Improves readability
  • Follows BDD pattern

These features are commonly covered in REST Assured Interview Questions to evaluate automation skills.

🔹 6. How do you add query parameters in REST Assured?

📖 Description

Query parameters are used to filter or customize API responses. REST Assured provides the queryParam() method to add these parameters easily. Multiple query parameters can be chained together. They are commonly used in search APIs, pagination, and filtering scenarios. Query parameters are appended to the URL after a question mark. Proper use of query parameters ensures accurate API testing.

💻 Code Snippet

given()
    .queryParam("page", 2)
.when()
    .get("/users")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • Use .queryParam()
  • Supports multiple params
  • Used for filtering data
  • Common in pagination APIs

Response validation scenarios frequently appear in REST Assured Interview Questions.

🔹 7. How do you send path parameters in REST Assured?

📖 Description

Path parameters are dynamic values embedded in the URL path. REST Assured allows you to define them using the pathParam() method. This avoids hardcoding values and improves test flexibility. Path parameters are replaced in the endpoint using placeholders. They are commonly used for resource identification like user IDs. This approach enhances reusability in test scripts.

💻 Code Snippet

given()
    .pathParam("id", 2)
.when()
    .get("/users/{id}")
.then()
    .statusCode(200);

🎯 Interview Takeaway

  • Use .pathParam()
  • Avoid hardcoding URLs
  • Improves reusability
  • Used for dynamic endpoints

🔹 8. How do you validate response body in REST Assured?

📖 Description

Response body validation ensures that the API returns correct data. REST Assured uses Hamcrest matchers to validate JSON or XML responses. You can validate fields, arrays, and nested objects. This is critical for verifying business logic. Body validation ensures not just success but correctness of data. It is commonly used along with status code validation.

💻 Code Snippet

given()
.when()
    .get("/users/2")
.then()
    .body("data.id", equalTo(2));

🎯 Interview Takeaway

  • Use .body()
  • Supports JSON validation
  • Works with Hamcrest
  • Validates business logic

🔹 9. How do you parse JSON response in REST Assured?

📖 Description

Parsing JSON responses allows extraction of specific values for validation or reuse. REST Assured provides jsonPath() to navigate JSON structures easily. It supports extracting strings, integers, lists, and nested values. This is useful in chaining API calls where one response feeds another request. JSON parsing reduces dependency on static values. It is essential for dynamic testing scenarios.

💻 Code Snippet

Response response = get("/users/2");
String name = response.jsonPath().getString("data.first_name");

🎯 Interview Takeaway

  • Use jsonPath()
  • Extract dynamic values
  • Supports nested JSON
  • Useful for chaining APIs

🔹 10. What is Response object in REST Assured?

📖 Description

The Response object represents the complete API response returned by the server. It contains status code, headers, and response body. It allows testers to extract values and perform multiple validations. and to logged or stored for later use. Using Response object improves flexibility in test scripts. It is commonly used in complex automation scenarios.

💻 Code Snippet

Response response = get("/users/2");
System.out.println(response.getStatusCode());

🎯 Interview Takeaway

  • Stores full response
  • Includes body, headers, status
  • Used for extraction
  • Supports multiple validations

11. How do you handle headers in REST Assured?

📖 Description

Headers provide additional information about the request such as authentication and content type. REST Assured allows headers to be added using the header() method. Multiple headers can be chained in a single request. Headers are essential for secured APIs and content negotiation. Proper header handling ensures correct communication with the API. It is widely used in authorization scenarios.

💻 Code Snippet

given()
    .header("Authorization", "Bearer token")
.when()
    .get("/users");

🎯 Interview Takeaway

  • Use .header()
  • Supports multiple headers
  • Common for auth & metadata
  • Critical for secured APIs

🔹 12. How do you perform POST request with JSON body?

📖 Description

POST requests are used to create new resources on the server. In REST Assured, JSON payloads are passed using the body() method. The request must include a proper Content-Type header. The response is usually validated with status code 201. JSON body can be hardcoded or read from external files. POST is widely used in data creation scenarios.

💻 Code Snippet

given()
    .contentType("application/json")
    .body("{ \"name\": \"John\" }")
.when()
    .post("/users")
.then()
    .statusCode(201);

🎯 Interview Takeaway

  • Use .post()
  • Pass JSON via .body()
  • Set Content-Type
  • Validate 201 response

🔹 13. What is Content-Type and how do you set it?

📖 Description

Content-Type specifies the format of the request body sent to the server. Common types include application/json and application/xml. It is mandatory for POST and PUT requests. REST Assured allows setting it using contentType() method. Incorrect Content-Type can lead to API failure. It ensures proper parsing of request data by the server.

💻 Code Snippet

given()
    .contentType("application/json");

🎯 Interview Takeaway

  • Defines request format
  • Required for POST/PUT
  • Common: JSON/XML
  • Prevents parsing issues

🔹 14. How do you log request and response in REST Assured?

📖 Description

Logging is essential for debugging failed API tests. REST Assured provides built-in logging using log().all(). It can log request, response, headers, and body. Logging helps identify issues quickly during execution. It is especially useful in CI/CD pipelines. Selective logging options are also available for better control.

💻 Code Snippet

given()
    .log().all()
.when()
    .get("/users")
.then()
    .log().all();

🎯 Interview Takeaway

  • Use .log().all()
  • Helps debugging
  • Logs request & response
  • Useful in pipelines

🔹 15. How do you validate response time?

📖 Description

Response time validation ensures that API performance meets expectations. REST Assured provides the time() method for this purpose. It can be validated using Hamcrest matchers. Performance validation is important for SLAs. Slow APIs can impact system performance. It is often combined with functional validation.

💻 Code Snippet

given()
.when()
    .get("/users")
.then()
    .time(lessThan(2000L));

🎯 Interview Takeaway

  • Use .time()
  • Validates performance
  • Ensures SLA compliance
  • Uses matchers

🔹 16. What is Hamcrest matcher in REST Assured?

📖 Description

Hamcrest is a library that provides matcher methods for assertions. It improves readability and expressiveness of validations. Common matchers include equalTo(), hasItem(), and containsString(). It is used extensively in response body validation. Hamcrest integrates seamlessly with REST Assured. It makes assertions more descriptive.

💻 Code Snippet

.then()
    .body("data.id", equalTo(2));

🎯 Interview Takeaway

  • Assertion library
  • Improves readability
  • Common in validation
  • Works with REST Assured

🔹 17. How do you extract values from response?

📖 Description

Extracting values from response is useful for dynamic testing. REST Assured provides extract() method for this purpose. Extracted values can be reused in subsequent API calls. It supports extracting different data types. This is essential for chaining APIs. It reduces dependency on hardcoded values.

💻 Code Snippet

int id = given()
.when()
    .get("/users/2")
.then()
    .extract()
    .path("data.id");

🎯 Interview Takeaway

  • Use .extract()
  • Enables chaining APIs
  • Supports dynamic data
  • Reduces hardcoding

🔹 18. How do you reuse request specification?

📖 Description

RequestSpecification allows defining reusable configurations like base URI, headers, and authentication. It helps avoid duplication across tests which improves maintainability and scalability of frameworks. It is commonly used in large automation projects. Centralized configuration ensures consistency. It is a best practice in framework design.

💻 Code Snippet

RequestSpecification req = given().baseUri("https://reqres.in");req.when().get("/users");

🎯 Interview Takeaway

  • Reusable configuration
  • Reduces duplication
  • Improves maintainability
  • Used in frameworks

🔹 19. What is baseURI in REST Assured?

📖 Description

Base URI is the root endpoint for API requests. It avoids repeating the full URL in every test. REST Assured allows setting it globally using RestAssured.baseURI. This improves readability and maintainability. It is useful in environment-based configurations. Changing base URI becomes easier in centralized setup.

💻 Code Snippet

RestAssured.baseURI = "https://reqres.in";

🎯 Interview Takeaway

  • Root API endpoint
  • Avoids repetition
  • Centralized configuration
  • Improves maintainability

🔹 20. How do you handle different HTTP methods?

📖 Description

REST Assured supports all HTTP methods such as GET, POST, PUT, DELETE, and PATCH. Each method is used for specific operations like retrieving, creating, updating, or deleting resources. These methods are directly available as functions in REST Assured. Understanding them is fundamental to API testing. They form the basis of CRUD operations. Proper usage ensures accurate test coverage.

💻 Code Snippet

get("/users");
post("/users");
put("/users/2");
delete("/users/2");

🎯 Interview Takeaway

  • Supports all HTTP methods
  • Used for CRUD operations
  • Core API testing concept
  • Direct method usage

🔥 Final Conclusion

If you can confidently explain these 20 questions with code, you’re already operating at a strong mid-level automation engineer standard.

But here’s the brutal truth 👇
Most candidates stop here — and that’s why they get rejected.

To crack Test Lead / SDET / Architect interviews, you must go beyond:

  • Token handling
  • Framework design
  • Request/Response spec reuse
  • CI/CD integration
  • Data-driven API testing

External Links:

1. Official REST Assured GitHub (Primary Source – MUST HAVE)

2. REST Assured Official Website (Detailed Docs)

3. REST Assured Javadoc (Advanced / Interview Level 🔥)

4. Maven Dependency (Very Important for Setup Questions)

Have a look on Testng related Blog  TestNG Automation Framework – Complete Architect Guide for Enterprise CI/CD & Parallel Execution

Looking for Cucumber related Blog For a complete BDD implementation guide, read our Cucumber Automation Framework – Complete Beginner to Advanced Guide.

Have a look on API Authentication related Blog , read our The Ultimate API Authentication guide

Don’t Know Playwright , check our Playwright-Interview-Questions-Guide

Tags:

Author

Ajit Marathe

Follow Me
Other Articles
No Comment! Be the first one.

Leave a Reply

Your email address will not be published. Required fields are marked *