Top 15 API interview questions for Software Testing

In this post will discuss the top 15 API interview questions that can be asked during your testing interviews. If you haven’t readed our article about API testing, click here to read it first.

in this article, we will  discuss top 15 API interview questions which can be asked during your interviews

1.) What is API Testing?

API stands for Application Programming Interface. It specifies how two software components should interact with each other. In API Testing, we test APIs directly. It is a part of integration testing. We check whether the API meets some of our expectations like reliability,security, functionality, and application performance in API testing. Our primary focus in this testing is on the business logic layer of the software architecture.

2.) What are the types of API Testing?

  • Functional Testing
  • Validation Testing
  • Unit Testing
  • Load Testing
  • UI Testing
  • Security TEsting
  • Penetration Testing
  • Fuzz Testing
  • Run time error detection
  • WS Compliance Testing

3.) What are the tools used for API Testing?

  • Runscope
  • Curl
  • Postman
  • Fix
  • Check
  • SoapUI
  • HTTP
  • REST
  • JMS
  • UDDI

4.) What do you mean by API Test Environment?

For API, setting the test environment is not an easy task. It requires a lot of effort in establishing the test environment. For developing the test environment, You need to configure both server and database, and it is done according to the software application requirements. There is no GUI(Graphical User Interface) in API Testing.

After the installation, API is verified for its proper functioning.

5.) What is API Framework?(Mostly asked API interview questions)

The API Framework is described by the config file, which consists of a list of all the APIs required to be activated and activated for any particular program run. API Framework is mandatory as every test run does not require all APIs.

The API Frameworks are the code libraries that provide standard functionality when creating your APIs. This framework is a platform that is used for developing software applications. It is a type of foundation on which the developer can build a software application.

6.) Write some templates for API documentation.

These are some mostly used templates:

  • Slate
  • Swagger
  • Miredot
  • FlatDoc
  • API Blueprint
  • RestDoc
  • Web Service API Specification

7.) What is Soap?

Soap stands for Simple Object Access Control. Soap is an XML based protocol that helps in exchanging information between computers. It is a kind of messaging protocol developed by Dave Winer, Don Box, Bob Atkinson, and Mohsen Al-Ghosein in 1988. It relies on the application layer protocols like HTTP.

8.) What is the Rest API?

Rest API stands for Representational State Transfer, and it defines a set of constraints used for creating web services. It is a set of functions that developers use to perform and receive responses. Rest API is an adequate standard for API designing, which uses HTTP protocols.

The Six architectural constraints are defined in Rest API:

  • Uniform Interface
  • Stateless
  • Cacheable
  • Client-Server
  • Layered System
  • Code on Demand

9.) Differences between Soap and Rest API.(Mostly asked API interview questions)

SoapRest API
It stands for Simple Object Access Control.It stands for Representational State Transfer.
Soap is a protocol.Rest is an architectural pattern.
It works with an XML pattern.It works in different ways, like XML, Html,Json, etc.
Soap doesnt support caching.Rest API supports caching.
It is slower than Rest.It is faster than Soap.
Soap uses Web Service Description Language.Rest API uses Web Application Description Language.
It isn’t easy to implementIt is easy to implement.

10.) What are some APIs which are quite popular?

These are some of popular APIs:

  • Twitter
  • YouTube
  • Facebook Messenger
  • MailChimp
  • Slack
  • Amazon S3
  • Google Maps
  • Google Fonts
  • FullContact
  • Stormpath
  • Dropbox
  • Twilio

11.) What are some most commonly used HTTP Methods?

  • GET: This method is used to request data from the server.
  • POST: It is used to send data to a server for creating/updating resources.
  • PUT: PUT replaces the existing file/resource in the server.
  • DELETE: It removes/deletes the specified resource.
  • OPTIONS: OPTION method describes the communication options for the target resource.
  • HEAD: It is identical to the GET method but without the response body.
  • PATCH: It is used to apply the partial modification to a resource.

12.) What is API Builder?

API Builder is a PL SQL program which consists of Four SQL files.

  • One file is used for setting API parameters ad starting the process.
  • The Two files are used to create temporary tables and master package.
  • The fourth file is used to develop the spooled output of the file into a record called output_script.sq.

13.) What is Test API?

Test API is a set/Library of test building that enables both testers and developers to create testing tools and automated test suites for .NET and win32 applications. Test API offers a set of basic building blocks, algorithms, etc.

14.) What are the types of bugs that can be detected by API Testing?

These are the some types of bugs:

  • Stress
  • Reliability Bugs
  • Security Bugs
  • Unused Flags
  • Duplicate Functionality
  • Performance
  • Improper Errors
  • Multi-threading issues
  • Absence of error handling mechanism
  • Improper messaging

15.) Can we use the GET Request instead of PUT to create a resource?

NO, only PUT and POST methods are used to create a resource. The GET method is used to request data from the server/resource.