Latest API Testing Interview Questions to Prepare

API Testing Interview Questions


API stands for application programming interface, which is known for its specific interaction between the various components. Function painting in the business logic layer API mainly resides or say concentrate when we talk about software architecture. API testing is based on the performance of a system with multiple API’s which is required with significant testing to be performed like testing tools, the interaction between API and application, and code is written to complete the test. However, there are not any fixed patterns for the questions asked in the interview. It may differ, but candidates must have experience of working on the subject. Several questions are based on the project on which you have to work. We will be discussing the API Testing Interview Questions with sample answers in this article.

API Testing Interview Questions

Some essential interview questions are:

  • What do you know about API testing?

Answer: For the proper building of software applications, API is a collection of routine tools protocols that are continuously required together. Several systems and software are based on multiple API, which can perform application performing interface testing. Interaction between API and application program this kind of testing includes various interactions between various or use multiple APIs.

  • Tell us about some standard tests which are performed on APIs?

Answer: With proper validation of API in data, the structure is to be updated. The return value of input condition-based. If any other event is triggered for interaction, a call to another API is raised. Wrong results for the return value can also be null. Database process killing and several other modifications of some resources with proper updates.

  • What do you know about the API testing environment?

Answer: Environment testing for API is a complex method to set up where the configuration of several servers and the database requirements is done as per the software application. Unfortunately, this form of testing with the graphical user interface is not available. However, with proper functioning after the API is installed, initial involvement that invokes API in this process is set up with a properly defined set of parameters that test results can be analyzed.

  • Tell us about the testing approach of the API?

Answer: Using the testing techniques with appropriate test cases which value the boundaries like analysis, equivalence class for, or functionality verification. The value-added parameters of two or more with verification through the calls of combination. Basic functionality of API with proper scope and definition. Accurate input parameter with the proper definition. The results with expected result test case execution and its comparison with results. The connection with the file with proper determination of API behavior under several conditions.

  • Tell us about the tools used for testing for API?


  • Curl
  • Automated API Testing
  • Runscope

These are tools that are used for API testing, and there are several others tools also.

  • Define the tools which are used for automation testing of API?

Answer: Development in API testing with automation testing is a must when we talk about agile language and how the code is written, which is also an important factor. Some tools used for API automation testing are:

  • NUnit and JUnit are all the tools used for testing where the code is written in .net and Java respectively.
  • HTTP Master
  • PARASOFT does not have any graphical user interface and this testing tool runs on various platforms which are used in testing API.
  • HP QTP/UFT has unified functional testing without a user interface like a web service. This tool is used for systems without users with unified functional testing.
  • SOAPUI with effective test coverage, creating complex validation scripts and test cases which are the open-source API testing tools that are considered to be the best testing tool with great features.
  • What do you know about API frameworks?

Answer: The configuration file consists of the list of APIs required to be activated. A particular program run with an activated API framework is described as a configuration file that lists all the required API is essential eyes every test does not run. The configuration file aims to describe or analyze the component while a test runs with every configurable component.

  • Explain the documentation of API?

Answer: Any foundation which is well aware of the fact that there has to be good documentation which serves as a great reference with proper accessing of the library or working with a program although with any such documentation content source properly out of sketch for delivery which consists of relevant information related to each function. Tools used for documentation are Javadoc and Doxygen.

The categories which are being used for testing the documentation with the parameters which mainly revolves around are:

  • Function-Related Links
  • Messages that can occur with syntax and type of errors.
  • Description of Function
  • Sequence, elements, and syntax are the required parameters.
  • Tell us about the challenges faced during the testing of API?

Answer: The API testing will face several challenges as a part of every form of testing that goes the same. Challenges faced during the testing of API are: 

  • Categorize Parameters
  • When it is used with combination in the first and foremost challenge is to select with appropriate parameters.
  • Inadequate coverage while testing may lead to proper sequencing of calls which is required.
  • Validation and verification of output.
  • Jio is not available in this case if another important challenge you face is to provide input values which are very difficult as a GUI.
  • What is the template which is mainly used for documentation of API?

Answer: Some easy and simple API documentation like:

  • Specification for Web service API
  • Swagger
  • API Blueprint
  • Slate
  • Miredot
  • Reston
  • FlateDoc
  • Give some examples of API which are very well known and popular?

Answer: Various examples are most known and popular are:

  • YouTube: Live streaming, video players, and several others used for API with various functions including these things.
  • Google Map API: With the help of flash interface in JavaScript these are designed mainly for mobile and desktop.
  • Twitter: With the search for Twitter the API for Twitter is generally into categories one which is accessing data and the second one for interacting with the search for Twitter.
  • Amazon Advertising API: Accordingly does its functionality in advertise for their product to discover the Amazon is known for their product and their advertising API access. 
  • Under API testing what are the methods?

Answer: Several methods for API testing are as follows:

  • Determination of the effectiveness and efficiency of API documentation testing.
  • Web UI testing and end-to-end integration testing.
  • For creation and execution of automatic testing with a script that regularly interacts with the execution of API calls.
  • Validity for all types of authentication with security testing and penetration testing.
  • Obtaining consistency with its reliability and usability testing.
  • Functional testing and unit testing.
  • Performance under load testing.
  • For deletion creating and listing the numbers of calls by discovering that have been documented in API.
  • Performance of API testing, what are the types of issues which have been observed?

Answer: Why testing the performance There are several issues which are associated with them and observed while analysis through the form of testing and some common category with some new different types, the problems are:

  • Improper and multithreading handling issues concerning the connection with the API for reliability issues.
  • Improper messaging issue.
  • Performance and stress issues.
  • Value has excellent knowledge that that of input passing incorrect with argument. 
  • In several cases missing out on some required arguments and functionality.
  • Functionality with repetition and redundancy.
  • A handling mechanism with the absence of our inconsistency.
  • For automation testing for API, which is determined as the most suitable form?

Answer: It is observable that API testing is now preferred with the most suitable and considerable GUI testing. However, some reasons for concern with the statement are:

  • Fast feedback with easier and proper maintenance.
  • Under test verify all the functionality and part of the system very effectively.
  • Providing the most stable interface.
  • Tell us about some of the warnings and alerts you know about API?

Answer: When there is some issue, then as per the need, the outcome becomes an error, and the warning described in a proper format in different modules may be several warnings. Other types of warning which may occur in models are:

  • Warning for the missing module.
  • Warning for parameter validation.

Different types of error which may occur are:

  • Error message with some standard.
  • Documentation error.
  • Missing the error of modules.
  • EThe error of Parameter validation.

Way Forward

With analysis of functional domain knowledge, the above or the API interview question may be helpful to face the interviewer and find the focus on API’s functionality. Although interviews are interested in testing your skills and some basic knowledge that is more critical and if the candidate has better understanding with that application and has excellent knowledge that May gains when working with the technology. These are some basic questions that may enhance your skills to face the interview and collect basic information based on API.

Also read Web API Interview Questions and Sample Answers

Latest API Testing Interview Questions to Prepare

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