The API testing interview questions and answers may help you pass the interview and have a better future, and this blog has information on this technology.

It ensures that an API works appropriately and responds to user and application queries; this technique is essential for software system integration and communication, preventing faults that might interrupt an application or system.

This blog will cover the Rest API testing interview questions, their kinds, and recommended practices for establishing a successful API testing plan.

1. What is API?

API stands for Application Programming Interface, which allows users to interact with the service provider; it provides a set of rules and protocols that users can follow to access the services provided by the service provider.

2. What is the purpose of API testing?

API testing is a crucial aspect of digital experiences, as it drives information and marketing campaigns, connects mobile apps, and streamlines internal operations.

3. What is API testing?

API testing is a type of software testing that involves testing API’s as part of integration testing to ensure they meet expectations for functionality, reliability, performance, and security.

4. What is the main focus of API testing?

API testing mainly focuses on the business logic layer, where business logic processing occurs, and transactions between the user interface and the database occur.

5. What is the difference between web services and RESTful web services?

Web services are applications accessed over the web or network, while RESTful web services follow the REST (Representational State Transfer) architectural style.

RESTful web services are less full-featured than complete web services.

6. What is a web application?

A web application is an application that allows users to communicate over the web or network, and Communication occurs through protocols such as HTTP, which ensures specific standards of communication occur between one end and another.

7. How is a request processed in a web application?

When a user enters a keyword and clicks on the “post-mind” keyword, the backend processes the request, collects all information from the server side, decrypts it into a JSON format or XML format, and returns it to the client, and the response is displayed in a readable form on the server side.

8. What is the three-tier architecture of web applications?

The three-tier architecture of web applications includes a client, business, and data layers.

The client layer is responsible for the interaction between the client and server, the business layer handles the data processing, and the database layer stores information about services, products, payments, and transactions.

9. What is the role of API in web applications?

API plays a significant role in providing a comprehensive and efficient way to interact with web applications.

By understanding the process of passing requests via protocol and securely processing them, developers can better serve their clients and ensure the success of their applications.

10. What is the role of the client layer in web applications?

The client layer is where the user interface (UI) is designed to process the request.

11. What happens when a user enters a keyword in Google’s search area?

The request is processed based on logic in the business layer and interacts with the database layer, and Responses are then sent back to the client or the UI.

12. What is the role of the business layer in web applications?

The business layer handles the data processing, while the client layer interacts with the UI and data.

13. What happens when the user needs to check a hundred emails in the Gmail application?

The request goes to the business layer, which hits the server to find the mail for the specific Gmail account holder; the business layer writes a query on the database, gets all the emails, and selects them from the client’s display.

14. What is the role of the database layer in web applications?

The database layer interacts with the business and client layers, storing and retrieving data.

15. What is the JSON format?

The JSON format is a lightweight data-interchange format that is easy for humans to read and write and for machines to parse and generate.

It transmits data between a server and a web application in a text format.

16. What is the purpose of converting JSON to a readable format?

The purpose of converting JSON back to a readable format is to help understand the business flow and network development, it also helps ensure the user’s request is processed correctly, and the data is processed back to the client.

17. What is the role of the business layer in processing a user’s request?

The business layer plays a crucial role in ensuring that the user’s request is processed correctly and that the network takes the necessary time to process the data.

18. How can the developer check the network flows of a website using “Inspect”?

The developer can check a website’s network flows using “Inspect” by clicking on the “Network” tab, which displays all network requests and responses.

19. What is the status code 200?

The status code 200 indicates that the request has been processed successfully.

20. What are the request details in the response headers?

The request details included in the response headers are the query parameters, the request method, the response headers, and the response body.

21. What can the developer review in the development code for the service?

The developer can review links, responses, and variables in the development code for the service; they can also see how the business logic is implemented, how the backend services are called, and the timings of the request and response requests.

22. What is the importance of network logs for web applications?

Network hooks are vital for comprehending the actions executed on a web application, displayed from the UI level.

23. What is the distinction between desktop applications and web applications?

Desktop applications installed on a machine do not require a network to communicate with them, and web applications always need a network.

The Internet is always necessary for web applications; desktop applications, however, can be accessed without a network.

24. What do you understand by re-useability in web services?

Re-useability refers to the reuse of a service multiple times without rewriting it, a service is a function that performs a task for you, providing output based on your request.

For example, a calculator service can have functions like addition, subtraction, multiplication, division, modulus, assign, percentage, and more.

25. What is a public method in a class calculator?

A public method in a class calculator is a method that any object or user can call; the technique can take input from the user and perform a specific task, such as addition, subtraction, multiplication, division, modulus, assign, percentage, and more, the result is stored in a variable, which can hold specific values.

26. What is the role of network logs, services, API testing, and web services in web applications?

All of these aspects are crucial to understanding the functionality and re-useability of web applications, and re-useability and re-useability; developers can better understand how to create and maintain web applications that meet the needs of their users.

27. What is a web service?

A web service is a collection of functions or APIs deployed on one server and can be accessed by users via the Internet.

28. How does a web service work?

A web service allows users to interact with the provider through an application programming interface (API), users can call the services’ functions and methods, which are available on the server.

29. How is a request sent in a web service?

A request is sent in a web service using the HTTP protocol, and the URL is sent along with the request data, usually in JSON or XML format.

30. What is the difference between GET and POST requests?

GET and POST requests are two types of HTTP requests used to request server data; a GET request retrieves data from a server, while a POST request submits data to a server.

31. What is a JSON format?

JSON (JavaScript Object Notation) is a lightweight data-interchange format that is widely used for web services; it is a human-readable format that uses key-value pairs to represent data.

32. How is a JSON response reconverted back into a readable format?

A JSON response can be reconverted back into a readable format using a tool or library designed to parse and convert JSON data; these tools can extract the data from the JSON response and convert it into a format that is easier to read and understand for the end user.

33. What does an API do?

An API is an intermediate layer between two software systems, helping them communicate and process data.

34. What are the benefits of using an API?

APIs provide value to applications, make phones smarter, and streamline business processes.

35. What is the difference between API and graphical user interface testing (GUI)?

API testing is a method that focuses on the functionality of an application rather than its appearance or functionality, and it differs from graphical user interface testing (GUI) testing and requires less maintenance and effort than GUI testing.

36. What is the five-step process for API testing?

The five-step process for API testing involves documenting the testing requirements, setting up a test environment according to the plan, calling an API immediately to ensure no issues are found,

It’s combining application data with the API test to ensure that the application functions as expected under different conditions or input configurations and organising around the API test by asking questions about the target audience, customer, aspects being tested, problems being tested for, priorities to try, and potential outcomes.

37. Why is API testing necessary?

API testing is crucial for ensuring the smooth operation of applications and ensuring their functionality, reliability, performance, and security.

38. What should be tested on the API after creating testing boundaries and requirements?

After creating testing boundaries and requirements, the next step is to decide what to test on the API; this can be done by designing what to test for and creating test cases based on the requirements.

A basic guideline is identifying the most common parameters and conditions end users develop when calling APIs.

39. What are the different types of API testing?

There are multiple API testing types, including functionality, reliability, and load testing. Functionality testing checks if the API works as intended, while reliability testing ensures that the application can be consistently connected and lead to consistent results.

Load testing, however, is focused on reality and is a more realistic test.

40. What are the advantages of API testing over other kinds of testing?

API testing offers several advantages over other testing, such as being language-independent and graphical user interface (GUI) independent and offering improved test coverage.

API services have specifications allowing for automated tests with high coverage, including functional and non-functional testing; multiple techniques are available to find API test cases that could not be automated, improving test coverage through manual or automated API testing.

41. Why is API testing beneficial?

API testing is beneficial because it is language-independent, allowing for using any language regardless of the application’s development platform; it also offers improved test coverage and faster releases.

42. What are some challenges associated with API testing?

Some challenges associated with API testing include the lack of a graphical user interface, synchronous and synchronous dependencies, data management, and request and response issues.

43. How can API testing help reduce testing costs?

API testing helps reduce testing costs by identifying minor bugs early on, which will become more prominent during graphical user interface testing

44. What are some benefits of API testing over UI testing?

Some benefits of A P I testing over UI testing include language, graphical user independence, reduced testing costs, improved test coverage, and faster releases.

45. What are some challenges that can pose challenges in A P I testing?

Some challenges that can pose challenges in API testing include time constraints, lack of a graphical user interface, synchronous and synchronous dependencies, and data management.

46. What are web service keywords used for?

Web service keywords are used in API testing to test web service-based applications; they provide built-in commands for web UI, mobile, cucumber, and web service keywords.

47. How does the send request keyword work in API testing?

The send request keyword is used to send an HTTP request to the web server and verify the response; when a user executes this keyword, a web service call is made, and the response is verified to ensure that it meets the desired criteria.

48. What is the element features section used for?

The element features section checks the fair element property value; a command in API testing verifies that the specified value is present in the return data from a web service call.

49. What options are available for testing web service keywords in API?

The options for testing web service keywords in API testing are manual and script formats.

Choose the correct answers for your better understanding:

50. Which of the following is the full form of the Application Programming Interface?

Answer:  API

API

APL

AIP

51. Which protocol is used for communication between web applications?

SMTP

FTP

Answer:  HTTP

TCP/IP

52. What are the three layers of a web application?

Presentation layer, business layer, and data layer

The client layer, presentation layer, and data layer

Client layer, business layer, and network layer

Answer: Application layer, business layer, and data layer

53. What is the purpose of the business logic layer in a web application?

Store information about services, products, payments, and transactions.

To handle the interaction between the client and server.

Answer: To process requests and return responses in a secure manner

Display information in a readable form on the client side.

54. Which layer in a three-tier architecture handles user interface processing?

Business Logic

Database

Answer: Client

URP

55. What is the purpose of the URP in a three-tier architecture?

Handle user interface processing

Interact with the database layer

To retrieve data from the client’s display

Answer: To send responses back to the client or UI

56. How is the communication between the two endpoints to the two systems in a three-tier architecture?

Answer: JSON form

XML form

plain text form

binary form

57. What is the purpose of the business layer in a three-tier architecture?

Handle user interface processing.

Answer: Interact with the database layer

Retrieve data from the client’s display

Send responses back to the client or UI

58. What is a web service?

Answer: Collection of functions or methods deployed on the same server

The simple approach to sharing functionalities between different applications

An interface that allows users to interact with the service provider

A web application that communicates with another application

59. What is an API?

Interface that allows users to interact with the service provider

Collection of functions or methods deployed on the same server

Answer: The web application communicates with another application

A request is made through a URL

60. What is the purpose of a web service?

Answer: Make maintenance easier and reusability more beneficial

Provide the consumer with the latest data from the server

Charge or recharge users

Communicate with service providers through APIs and interface

61. What is a form size in a web service?

Protocol used to send a request

Answer: Amount of data sent with a request

The type of request made

Location of the request.

62. What is a base path in a web service?

Answer: Path added to a URL to identify a specific service.

Type of request made.

Amount of data sent with a request.

Protocol used to send a request.

Conclusion:

API testing is necessary to ensure the software application’s operation, stability, and performance; before deployment, it tests API endpoints, data formats, authentication, and permission to find and correct errors.

API testing helps developers guarantee their apps work with other services and provide a smooth user experience; it may also save expensive downtime, increase application resilience, and improve software quality.