Prepare To Excel Top 20 API Testing Interview Questions & Answers In 2022

Prepare To Excel: Top 20 API Testing Interview Questions and Answers In 2023

Almost every product or service today, first and foremost, revolves around bringing a great user experience to the table. This remarkable shift in the industry approach has rendered processes like API testing all the more important. It is now a critical part of a product’s lifecycle.

As such, the career prospects in API testing are multiplying and getting more interesting as the process gains more popularity. Organizations are now on the lookout for API testing experts to optimize their product offerings in a way that best serves their clients or customers.

To those who are fairly new to the concept, let’s first take a look at what API testing means today. When two different software is involved, enabling communication between them is of utmost importance.

This is where a computing interface called API (Application Programming Interface) comes to the rescue. API testing is a process that best reveals bugs or inconsistencies within a program or an application.

API testing essentially helps monitor the performance, security, and consistency of the programming interface. It also helps determine whether the interface is meeting the expectations because if one interface fails then the entire service goes for a toss.

Given that it is an important process that can be leveraged to polish a product, API testing has opened up new avenues for software developers. All aspirants have to do is equip themselves with the right set of skills, and technical knowledge that comes in handy during interviews.

Top 20 API Interview Questions and Answers

If you are an aspiring developer who wishes to pursue a rewarding career in API testing, we are here to help you prepare for all the right opportunities. Here is a comprehensive list of API testing interview questions and answers in 2023.

10 API Interview Questions For Freshers

1. What is API?

API stands for Application Programming Interface. It is designed to facilitate communication and data sharing between two software systems. It acts as an interface between two applications and allows the two software systems to communicate with one another. API is a collection of functions that can be executed by another software program.

2. What is API testing?

As the name suggests, API testing is the process of testing the APIs directly; right from their functionality, reliability, performance, to security. API is essentially the middle layer between the presentation (UI) and the database layer. It enables the communication and data exchange from one software system to another and validates the logic of the build architecture at the quickest.

3. What are the types of API testing?

Here are some of the most common types of API testing:

  • Unit Testing
  • Functional Testing
  • Security Testing
  • Load Testing
  • UI Testing
  • Runtime/Error Detection
  • Interoperability and WS Compliance Testing
  • Penetration Testing
  • Fuzz Testing

4. How do APIs work?

What an API does is that it takes a request, processes it. This may also involve data validation, database interaction, data processing, and then the resultant of this is sent back to the source. APIs provide an abstraction to the internal business logic as they are not exposed to the world.

5. What are some of the tools used for API testing?

The most popularly used tool in the market is PostMan. This tool helps to create manual and automated test cases for testing the APIs in a well-designed manner. Apart from this, there are different tools like JMeter, Parasoft SOAtest, SoapUI, Apigee, API fortress, JUnit, etc.

6. What is an API test environment?

For API the test environment is a quite complex method where the configuration of server and database is done as per the requirement of the software application. API testing does not involve a graphical user interface (GUI). API is checked for its proper functioning after installation.

7. What are the protocols used in API Testing?

Protocols used in API testing are HTTP, REST, SOAP, JMS, and UDDI.

8. What is an API framework?

API framework is described by the config. File which consists of the list of all APIs that are required to be activated and are activated for any particular program run. This is essential as every test run does not require all APIs.

9. What are some of the best API testing practices?

Here are some of the best practices:

  • Select the ideal API testing tool that best suits your project requirements.
  • Make sure to group test cases by test category.
  • Simulate the final environments for API testing.
  • Create test cases for all possible API input combinations.
  • Give due importance to negative and security testing.
  • Monitor and accurately record all API responses.
  • Always test for the typical or expected results and perform call sequencing.
  • Limit the tests from as many variables as possible by keeping it as isolated as possible.
  • Leverage the power of automation wherever possible.
  • Use API function calls to facilitate quick yet effective testing.

10. What is SOAP?

SOAP stands for Simple Object Access Control. It is an XML-based protocol that helps in exchanging information among computers.

10 Advanced API Testing Interview Questions

1. What are the tools available to document an API functionality?

Some of the popular tools used for achieving API documentation are JavaDoc, Doxygen, OpenAPI, Redoc, and Swagger UI.

2. What is the difference between API testing and UI testing?

UI testing primarily focuses on the look and feel of the application. In user interface testing the main focus is on how users can interact with app elements such as images, fonts, layout, etc. are checked. API testing allows communication between two software systems. API testing works on the backend also known as backend testing.

3. What needs to be verified in API testing?

In API Testing, we send a request to the API and then we analyze the responses based on the following parameters:

  • Data accuracy of the actual response with the expected response
  • HTTP status codes of the resultant API
  • Response time of the API
  • Error codes if the APIs are expected to throw an error
  • Authorization details

4. What are the different bugs that can be found in API testing?

Here are some of the bugs that can be found during API testing:

  • Duplicate or missing API functionality
  • Failure to handle negative test cases
  • Failure to handle a sudden spike in load
  • Failure to handle requests securely
  • Improper error responses and status codes

5. What are the major challenges faced during API testing?

Here are some of the major challenges faced during API testing:

  • Parameter Selection
  • Parameter Combination
  • Call sequencing
  • Output verification and validation
  • Providing input values which are very difficult because GUI is not available

6. What is Test API?

Test API refers to a set of APIs or library utilities that helps developers to create automated test cases for testing .NET or WIN 32 systems. It has a set of basic data building blocks, data types, data structures, etc.

7. What do you understand by Black Box Testing?

Black Box Testing is one of the methods in software testing where the testers evaluate the software functionality without the knowledge of the internal source code. This ideology can be applied in every branch of testing such as unit testing, integration testing, system testing, and acceptance testing.

8. Define REST API?

REST stands for Representational state transfer. It is an effective standard for API creation. To put it simply is a set of functions that helps the developers perform requests when the response is being received. Protocol interaction is made in REST API through HTTP.

9. What are the characteristics of REST?

Firstly, REST is stateless. With the use of the REST API the server has no status, we can restart the server between two calls, in spite of all the data being transferred to the server. In addition, Web Services uses the POST method to perform operations, while REST uses the GET method to access the resources.

10. What is Payload?

Payload is the most common term used in the case of REST APIs. It refers to the actual data sent to the server in the API request in different formats like JSON, XML, etc.

Enroll With Cyber Success – Excellent API Testing Classes In Pune

With APIs capable of transforming businesses; firms today are looking for expertise. The demand for talented individuals equipped with all the right skill-sets is on the rise.

To help aspirants grab the right opportunities and make a name for themselves in the industry, Cyber Success has designed an industry-oriented API Testing course. Students get hands-on experience with SOAP web services, POSTMAN tools, types of tests, and more.

Students also get access to – a curriculum designed by industry experts, group discussions, practical learning, opportunities to work on live corporate projects, excellent mentoring by industry stalwarts, and 100% placement assistance. To get started, contact us today at (+91) 9168665643, (+91) 9168665644, or drop an email at hello@cybersuccess.biz