50+ Top API Testing Interview Questions With Answers (2024)

In the present day, APIs (Application Programming Interfaces) have grown in significance and are used more frequently as technology progresses. Due to their dependence, APIs need to be rigorously verified to guarantee they fulfill quality standards. To help job seekers prepare for interviews focusing on API testing, we have compiled some important questions to help them revise the fundamental topics. 

Top API Testing Interview Questions and Answers

Q1. What is API Testing?

Application programming interface (API) testing is software testing that examines if the APIs live up to expectations regarding functionality, dependability, performance, and security. The purpose of API tests is to detect bugs or issues related to data processing in applications before it affects users during UI-level tests. This allows organizations to identify problems quickly and efficiently before releasing an application into production.

Q2. What are the most typical API testing methodologies?

The main categories of API tests include:

1. Functional Testing: This includes checking expected inputs with actual outputs.
2. Security Testing: Involves making sure authentication processes have been set up correctly.
3. Performance/Load Testing: Ensuring that APIs can handle large amounts of requests without slowing down or failing unexpectedly.
4. Usability Tests: Confirm that user experience meets baseline design requirements.
5. Error Handling Test: Detecting errors thrown by endpoints when invalid input values are submitted as part of test cases etc.

Q3. What automated testing tools do you employ for APIs?

Various automation frameworks, such as Postman, SoapUI NG Pro, Parasoft SOAtest, Katalon Studio, etc., help automate the API testing process.

Q4. How can an invalid response be identified in APIs?

Invalid responses from an API endpoint can be recognized by comparing the expected results with those received during test runs. In case of discrepancies, invalid responses should be investigated further for root cause analysis and resolution.

Q5. Explain the process of creating and executing test cases for APIs.

Creating test cases begins by looking at existing design documentation to understand all possible use cases related to an application or service being tested and its associated data/API calls that need to be verified against requirements specified within said documents/specifications.

Once a solid understanding is achieved, start constructing different types of tests, such as unit tests, functional tests, integration tests, etc., by capturing inputs & outputs matching with pre-defined conditions.

This is followed finally by the execution phase, where actual requests are sent through chosen automation tool(s) set up previously according to specific criteria defined while constructing individual scenarios i.e. regression testing that will require more comprehensive coverage than one-time smoke testing activity would typically involve.

Q6. Describe how to interpret and evaluate a RESTful Web Service request-response structure.

Like Swagger and Postman, open-source tools can help evaluate a RESTful Web Service request-response structure. Swagger provides an interface for testing out endpoints within the context of your application by allowing you to enter input values and analyze responses from server calls along with details about each call, such as status codes or response time, etc.

On the other hand, using Postman's vast library of available plug-ins will let developers create automated tests that validate API calls against predetermined conditions to immediately identify any discrepancies present in returned results when compared with the expected output.

Q7. How could someone debug errors encountered while running tests on an API?

Testers need to know web technologies like HTML/CSS, JavaScript & AJAX to understand what is happening behind the scenes. Debugging errors requires targeted Dev-related tasks such as analyzing Javascript stack traces / understanding service log messages; setting breakpoints on the code level (if applicable) during runtime; performing cross-browser validations (to make sure the same behavior is replicated across multiple platforms if necessary); going through recent commits applied over source control system/config files maintained under versioning mechanism hosted somewhere centralized, i.e., inside Git repositories OR just plain old text file stored either locally OR remotely via SSH connection, etc.

Q8. Name some security measures that need to be considered while performing API Testing.

• Ensuring secure data transfer between different systems.
• Using SSL (Secure Socket Layer) for encryption/decryption of confidential information sent over communication channels.
• Using authentication protocols such as OAuth / OpenID Connect for validating user identity & access rights.
• Setting up proper authorization roles and privileges checks before granting access to sensitive sections within an application or service.
• Performing regular scans using web vulnerability scanners specially designed for APIs.

Q9. Explain what makes up a good set of requirements when writing secure web service calls.

A good set of requirements should include the following elements:

• Secure transport layer – enabled by default;
• Access control matrix specifying which users have permission to perform specific operations;
• Input validation rules applied upon each parameter incoming via a Web Services call & whitelist all public facing endpoints where appropriate, etc.

Additionally, make sure those additional logs are being created whenever necessary, identifying source IP address, date time stamps, type of request made along with corresponding response code returned, etc.

Q10. List five elements or criteria necessary when developing successful web services.

1. Using the right protocol, i.e HTTP(S) - depending on the scenario if applicable.

2. Ensuring proper authentication & authorization mechanism is in place (if needed).

3. Having well-defined and structured data formats for inputs/outputs of the service being used

4. Easy-to-understand documentation describing all available APIs - like Swagger / RAML.

5. Performing regular stress tests, ensuring everything behaves as expected, even under high-load scenarios.

Q11. What experience do you have with penetration testing for APIs?

If you are experienced with penetration testing for API, you may answer this interview question in the following way: 

I have several years of experience conducting penetration tests on web applications, websites, and APIs. I am familiar with both automated and manual approaches to finding vulnerabilities in the underlying code base that attackers could use maliciously. I also understand how to create payloads capable of exploiting these weaknesses by constructing complex scripts using common attack vectors such as SQL injection, buffer overflow attacks, XSS exploits, etc.

Q12. How would you approach unit testing an API?

When it comes to unit testing an API, there are a few key steps that must be taken when beginning the process:

Firstly, ensuring the environment is correctly set up for performing test runs (i.e. databases, server-side code) will allow us to accurately assess each part of our application by providing consistent results from our target systems.

Secondly, validating all input parameters - checking ranges, types & user permissions. Thirdly, analyzing logs or report files- if any are generated after running a particular set; finally, testing edge cases that may simulate real-life scenarios where unexpected data presents itself.

Q13. Could you explain the purpose of tracking error codes during API testing?

Error Codes are essential for API testing as they provide a way to identify where issues are occurring in an application quickly. By tracking these codes, we can uncover problems that would otherwise be lost due to their complexity and hidden nature. Developers also use error codes to ensure their applications run without unexpected interruptions or breakdowns when facing unusual scenarios.

Q14. Can you give me some examples of non-functional testing that can be used when assessing API performance?

Examples include:

• Load Testing: Assessing an API's ability to handle high volumes of traffic while maintaining speed and accuracy;
• Stress Testing: Examining response times under conditions intended to simulate extreme load on system resources;
• Volume Testing: Evaluating changes in data output at different levels of usage ;
• Performance Testing: Identifying areas of code where improvements could make to improve speed response; 
• Security Testing: Confirming level security measures implemented.

Q15. What are the advantages of API testing over other software engineering tests?

The advantages of API testing can provide quick feedback about system integrations, data flow & other complex scenarios, which may be difficult to assess through conventional unit or functional tests. With APIs, we have more direct access to core components instead of using the user interface layer when performing our assessments, leading to shorter timeframes for successful implementation.

In addition, it is much easier to identify & isolate bugs associated with an API than locate User Interface-related issues. Finally, using networks such as TDD (test-driven development) frameworks will allow us safe deployment environments which facilitate rapid feedback loops for early bug detection, reducing costly delays later.

Q16. Explain API test design scenarios from scratch that are effective and efficient.

The best API test design approach to crafting effective test cases begins by first understanding business requirements and any existing documentation regarding how the application or feature should work in given circumstances before heading toward the scripting phase.

Once all information has been collected, begin writing out the basic workflow, either directly code based upon the language being used or specify boundaries for each input field variable to reach maximum coverage quickly, establishing relationships between modules and parts. This helps keep complexity lower while ensuring comprehensive testing.

Q17. What programming language is best for API testing?

It depends on the project and your specific requirements, but popular choices for API testing include Python, JavaScript, Java, and Go.

Q18. What are the top API testing tools on the market today?

Popular tools include Postman, SoapUI, Apigee Console, and Katalon Studio.

Q19. How can I test a distributed software system using an API tester tool?

You can use a distributed software system testing tool such as Selenium to test APIs across multiple machines or devices in parallel using shared data models that generate real-time reports of performance metrics like response time and error rates.

Q20. Are there any unsed flags that can be used to optimize API tests and results?

Yes, some unused flags can be used to optimize API tests. For example, the debugging flag enables users to debug their test to find any errors or weak points within the code before running it live. Another flag allows access to logs related to automated processes, which helps users compare successes/failures across different runs of tests under various conditions each time they are invoked from their respective environments.

Q21. Does my GUI support all the resource representations required by APIs?

Yes – most graphical interfaces support several representations, including XML (Extensible Markup Language) files representing structured data types used in web services like JSON (JavaScript Object Notation). In addition, libraries included with these GUIs also grant users control over powerful resource management capabilities when dealing directly with external sources both online & offline concurrently throughout any given application’s life cycle session(s).

Q22. Explain the types of API testing.

API testing is validating an application programming interface (API). It involves sending requests to an API and verifying a response. Here are different types of API testing: 

• Functional Testing: This test verifies that the API functions properly with different parameters, such as input data format or boundary conditions. The goal is to ensure that all components in the system interact correctly during various transactions between them. (Know more)
• Usability Testing: This test focuses on user experience using the APIs. Factors like ease of use or readability are evaluated for better engagement with end users who consume these services regularly.
• Performance Testing: In this case, APIs must be tested under load to identify bottlenecks and weak points before going into the production environment & also optimizing it for better throughput/latency results should be known through establishing benchmarks & measuring improvements latterly in terms of execution velocities, etc.
• Reliability Testing: Validating whether given set criteria responses from servers remain the same every time over a period of time, especially when performing stress /load testing scenarios along multiple iterations while making full proof that no unexpected issues arise due to CI/CD pipelines while creating
• Backend testing: Validating the functionality, performance, and reliability of a system’s components. In software development projects, backend testing measures how well each component works individually and how they fit together as a whole.
• Black-box testing: It is a type of software testing in which the internal organization, conception, or execution of an application are unknown. The tester depends on the functional requirements given by a stakeholder rather than having access to the system's source code or any other confidential information.

Testing activities can include:

• Ensuring that data values are stored properly in databases.
• Assessing API responses.
• Verifying content delivery network (CDN) caching capabilities.
• Measuring response times for user actions such as clicking buttons or scrolling web pages.

Level testing is a kind of black box testing technique performed on an application or system to test the functional behavior, compatibility, and reliability. It typically includes Unit Level Testing, Integration Level Testing, System Level Testing, and Acceptance level tests aiming to verify end-user requirements by simulating real-life scenarios.

Q23. What types of bugs should we be aware of while testing the API?

Bugs that should be aware of while testing the API include input validation (validating any data coming in), boundary conditions, compatibility, and security bugs such as XSS, SQL injection, etc.

Q24.What is the scope of testing for this API?

The scope of testing for this API will depend on the requirements, ranging from user authentication to full suite Testing, including Functional Testing, Integration Testing, Security testing, and Performance/Stress testing.

Q25.What testing methods do we use to test the core functionality provided by this API?

Testing methods used to test core functionality could include automation frameworks along with manual exploratory tests focusing on positive & negative scenarios, edge cases, or system behavior when invalid/malformed input is given; also, validations like unit & integration tests might be required to ensure APIs don't break if new content sources are added later on.

Q26.Where can we get content sources to use when conducting tests on this API?

Content sources needed for conducting these tests usually comes from external services or existing databases depending upon the requirement; it would need careful structuration by creating proper query strings while requesting data via API calls so they return desired output accordingly.

Q27.What is the syntax of error messages when an API call fails? What are the improper errors?

The syntax of error messages when an API call fails typically includes a description of the issue and its cause and possible solutions to resolve it. Improper errors do not indicate why or how the problem occurred and, therefore, cannot be resolved quickly.

Q28. How can common test methods be applied to ensure the accuracy of an API?

Common testing methods for APIs involve:

• Validating response codes.
• Ensuring proper input/output negotiation with server requests.
• Executing performance tests to ensure efficient data retrieval within specifications set by design requirements.
• Verifying code correctness with automated tools such as static analyzers and other debugging techniques specific to each programming language used in the development process (i.e., unit testing).

Q29. Does the accessibility interface allow users with disabilities to utilize the APIs effectively?

Accessibility interface implementation allows users who have physical disabilities such as vision impairment to access websites through screen reader technology which can also help to utilize APIs more efficiently; this is usually done by providing visual cues which guide user interactions during their session so they know what action needs to be taken for them complete their tasks effectively on-site or via services offered by API providers like payment gateways etc.

Q30. Is there a suitable process for parameter selection while making calls within an API?

Parameter selection while making calls within an API should follow certain procedures created based on desired usage scenarios, i.e., authentication information, content type settings, error code mapping, appropriate HTTP headers configuration, etc., all of which should be carefully taken into consideration while designing interface configuration.

Q31. Are adequate resources available for the identification of resources and debugging any issues encountered while using the APIs?

It is important to have adequate resources available for identification and debugging issues, such as; making sure proper response code conventions are used to indicate successful return values or errors respectively, analyzing web server logs so that any discrepancies can be addressed swiftly before the deployment stage, development documentation research, etc.

Q32. Are measures taken to test if data is being sent correctly and securely from a target resource via APIs?

While sending data from target resources via APIs would need additional measures on the part of the design team during the development phase, like encrypting transmission payloads with secure algorithms along with a checksum mechanism through HMAC hash salting technique applied at both ends – client-side responsible for verifying message integrity upon receiving responses -as well as server end where there needs to stricter security constraints enabling only authorized access credentials into system’s infrastructure backbone ensuring no confidential information has been compromised during data transfer.

Q33. What communication options are used for the API request message?

The type of communication protocol and methods available to send a request message depends on the specific API implementation. Common protocols used to communicate with APIs include HTTPS (Hypertext Transfer Protocol Secure), FTP (File Transfer Protocol), or SSH (Secure Shell). There may also be proprietary formats that need to be specified when making an API call, such as XML-RPC or SOAP-based web service requests over HTTP/HTTPS.

Q34. How is Request Routing handled in the Business Logic Layer of the API?

Request routing is typically handled by setting up rules within the business logic layer that determine how incoming requests should be routed through various components of an application system's architecture, including databases, queues, third-party systems, etc. This helps ensure that traffic flows properly between various endpoints while ensuring data security along each step of the way throughout its journey across different elements of infrastructure and backend services powering your application system ecosystem.

Q35. Does this API utilize Representational State Transfer (REST) architecture?

It depends on which particular RESTful architecture has been implemented - but generally speaking, most modern APIs use some form of Representational State Transfer (REST) architecture. This is because RESTful architectures are created for transferring data between different applications and provide a certain level of scalability, flexibility and robustness compared to other communication protocols, such as SOAP web services or XML-RPC calls.

Q36. Is Direct Method Invocation an available option when making calls to this API?

Direct method invocation refers to the ability of two separate applications to communicate over a network call without going through any intermediary server or application layers between them. Depending on which particular API has been implemented, it may be possible that direct method invocations are supported – but generally speaking, most modern APIs do not support it due to security reasons and performance implications associated with opening up direct connections across multiple systems linked together over the same network environment.

Q37. Give an example of a valid response body structure returned from this API call.

A valid response body typically includes various headers containing information about status codes, content types, etc., followed by an actual JSON/XML payload containing requested data points (i.e. records).

An example might look something like this:

{"status": 200, "contentType": "application/JSON," "data" :{ "userId": 1, "name": "John Smith"} }

Q38. How can we ensure that the software application created meets all standards?

When creating a software application, ensuring that the code follows all recommended standards is important. This includes ensuring the code meets industry best practices for readability and organizational structure, and compatibility with other systems or frameworks used in the project. 

Q39. What techniques should be implemented when making a POST request for API testing?

Making POST requests during API testing requires sending data in a specific format over HTTP(s). The most common way is using JSON, which allows complex data structures like lists or dictionaries to be transferred between scripts running on different hardware/software platforms (e.g., client-server). It's also possible to transfer more traditional text-encoded forms according to RFC1866, such as HTML form submissions. Still, these are not suitable for modern RESTful APIs where each resource has its own URI endpoint & verb combination representing what action should be taken by the server when receiving said request.

Q40. What changes and advancements do you see in store for future of software testing?

Software Testing will continue evolving towards automating tests further through AI techniques that allow machines to learn how a system works after being given some hints about its architecture; additionally, IoT devices may start requiring special consideration from test engineers so they can understand edge cases commonly unseen during traditional development cycles due make use of their limited resources effectively and securely.

Q41. How can one troubleshoot inconsistent errors encountered during API tests?

Inconsistent errors encountered during API tests should be investigated using a combination of logging techniques to pinpoint the source of the issues, varying from basic debug prints with important data in log files or more complex debugging tools like setting up breakpoints & watches within code while a debugger software is executing it. Once you've identified what is causing the issue, further testing can take place to reinforce your findings and make sure any potential fix works as expected.

Q42. When dealing with an incompatible error, what steps could be taken to resolve it successfully during API testing?

When dealing with an incompatible error during API Testing, the first step is to double-check that all components are compatible. For example, if you're running a web service, then chances are high that there could be compatibility problems between server & client scripts due to different versions not being synchronized correctly.

Furthermore, ensure that all parameters used comply with standards set out by RFCs (which define how two pieces of software must interact over network protocols) so communication doesn't get disrupted unexpectedly at any point throughout the process.

Q43. How does a graphical user interface (GUI) play a role while performing an API test cycle?

The graphical user interface (GUI) plays an integral role while performing API test cycles as it allows testers visually understand the complexities associated when working around multiple programs concurrently without having to dig deep into underlying systems architecture. This way, users can still explore limits safely through UI/UX controls & quickly verify any bug reports or edge cases within the codebase before being pushed live in production.

A graphical user interface can provide a user-friendly interface to quickly identify API testing issues, allowing testers to verify bug reports and ensure all components are compatible before pushing any changes live.

Q44. What measures need to be taken to build a stable interface while creating a Standard for API creation?

Building a stable interface during the process of creating a Standard for APU creation requires several steps:

• Firstly, you need to identify what kind of hardware/software present will be used and ensure that it's compatible between all components involved;
• Once compatibility is confirmed, proceed by designing user experience with best practices in mind, followed by testing different scenarios under supervision (such as automated tests);
• Lastly, use debugging techniques if necessary to further refine the end product and make sure everything works as expected before going live.

Q45. Explain the principles of the API test that should be considered while designing a plan.

When designing an API test plan, some important principles to consider include validation of the data received from a request and response, authentication/authorization testing for access control, error handling to ensure appropriate messages are sent when errors occur, security testing that verifies correct encryption is used during the transmission of sensitive data, load, and performance scaling tests are used to identify any limits in throughput or latency on the server side.

Q46. How does a Uniform Resource Identifier (URI) factor into API testing?

A Uniform Resource Identifier (URI) is necessary when accessing APIs because it contains all the components needed to make requests via HTTP methods such as GET and POST, which servers use to determine how to respond accordingly. It allows users (or applications) to access resources available through web services with specific locations defined by URIs so that two programs can exchange information across different networks connected over the internet without requiring mediation from a third-party application like SOAP or JSON RPCs.

Q47. Why is stateless communication important in the context of API testing?

Stateless communication between client & server plays an important role in API Testing since there is no persistent connection maintained between both ends, leading to communication faster & efficiently due to its ability to handle multiple requests independently, resulting in higher scalability & robustness than stateful protocol tools such as FTP sessions, etc., This means goals set forth before beginning each session must be achieved before ending them.

Q48. What types of informational responses can be expected from running an API test?

Informational responses returned from an API test may include results about the request sent, a response body containing relevant data requested (if any), a status code with a message regarding the success or failure of the request & optionally, headers that provide extra information necessary for debugging purposes such as HTTP version used in connection, etc.

Q49. What are the API parameters and their parameter combinations?

API parameters are components that form part of the URL and contain all essential information to process requests successfully. In contrast, parameter combinations refer to various possible ways.

They can be combined when making calls via getting/POST methods like path variables, query strings, and header fields, allowing users to access resources associated with specific URIs within given domain boundaries without having to worry too many details behind server-side operations. This is why imperative developers ensure these validations are properly set up before releasing applications into production mode otherwise, they can potentially lead to system failures if left unchecked during testing phases leading to further complications down the line. 

Q50. What is Functional Testing, and how can it be used for API testing?

Functional Testing is a process of testing that ensures the software program functions under its specified requirements. When conducting API tests, it involves ensuring each endpoint works as expected and errors are correctly handled, and any data returned is valid according to expected formats/types.

Functional Testing is a process that verifies the software program functions as specified according to its requirements. When performing API tests, functional testing involves verifying each endpoint works correctly and errors are handled properly with valid data returned in expected formats/types. 

Q51. How do you use validation testing to ensure the accuracy of an API?

Validation testing for an API can involve confirming all input parameters have the correct type or format and verifying all responses are formatted correctly according to specifications before they are sent back to the calling application or service provider. This form of validation helps ensure accuracy when passing messages between applications through APIs over a network such as HTTP(s).

Validation testing confirms that all input parameters have the correct type or format before they are sent over a network. This form of validation testing also verifies that any responses returned from API calls are in the expected formats/types before being sent back to calling applications or service providers. Validation Testing helps ensure accuracy when passing messages between services via APIs such as HTTP(s).

Q52. How could Fuzz Testing facilitate comprehensive functionality checks on an API?

Fuzz testing checks how resilient an API implementation is by sending unexpected inputs into endpoints within the system so potential vulnerabilities may be detected quickly (e.g., buffer overflow attacks).

By Fuzz testing, you can identify if there are any potential areas where malicious actors could gain access outside of normal use cases, thus increasing security levels in your product/application, which utilizes these APIs.

Q53. What steps should you take when conducting API documentation testing?

API documentation testing requires reviewing existing documents relating to functionality and performance results associated with calls made against different web services for correctness, accuracy & completeness.

In addition, checking test scenarios proposed to match actual methods from current user stories should also be conducted, like how long a response takes, what kind of errors get thrown back, and which data is returned in the event of success or failure.

Q54. By what means are requests formulated in a request body when making calls to an API using software programming languages such as Java or Python?

Requests are typically formed using software program languages such as Java or Python by providing an object representing the specified URL with parameters appended to it if needed (e.g. path/URL?query=parameter). The request body is generated from these objects with any necessary headers attached. JSON strings can also be used depending on the application architecture.

Q55. What are the major challenges and common challenges faced?

Major challenges faced when testing APIs include lack of clarity around API contracts and standards, incomplete test coverage due to time constraints, difficulties debugging code because source code may not always be accessible, poor performance-related issues if underlying infrastructure components aren't properly configured correctly, etc.

Common challenges revolve around writing and executing tests quickly enough for various endpoints and verifying that all edge cases have been sufficiently tested for proper functioning before release cycles.

Q56. What is the core functionality testing while performing API tests, and what is the API testing approach?

Core functionality testing in API tests includes:

• Verifying functional correctness.
• Validating if the responses returned are as expected.
• Checking for secure authentication protocols.

The approach used here is to have different test scenarios covering all of the mentioned aspects so that any potential bug or security issue can be identified early.

Q57. How can exhaustive testing of an API be done?

Exhaustive testing for APIs involves covering each part related to it, such as request/response format, input parameters, data type checks etc., along with multiple edge case scenarios before declaring a successful release of product feature involving API usage.

Q58. What are the phases in security testing that must be considered for API testing?

Security Testing phases generally involve identifying possible attack vectors by performing vulnerability scans and penetration tests using automated tools or manual methods to check for common threats like SQL Injection attacks Cross Site Scripting prevention measures etc. Other measures include logging requests & response timeouts on the server side securely, along with adding a layer of encryption over the transport channel.

Q59. How effectively does the software product perform authorization checks, functional paths and low-level input validation to create a safer system?

To evaluate the effectiveness of the software product in creating a safer system through authorization checks, functional paths, and low-level input validation, we need to investigate each of these elements independently.

Specifically, for authorization checks, we could test user roles against expected behaviors; for functional paths, review every possible flow based on all optional elements; finally, with low-level input, validate data types and equivalence classes. Doing so will provide insight into how effectively this software product creates a safer system.

Q60. Is the method validation used for the user inputs to ensure that only authorized requests are accepted through the REST server?

Yes, method validation should be used to ensure that only authorized requests are accepted through the REST server. This can include authentication schemes like OAuth and API Keys to authenticate user requests before allowing them to proceed further in the system.

Q61. What basic functionalities should be tested when implementing a limited-scope API?

When implementing a limited scope API, it is important to test basic functionalities like input validation, error messaging (when incorrect inputs are provided), successful data transmission from the client-side application to the server-side application, protection against malicious users with secured input formats, etc. It is also necessary for testers to check if all APIs function per defined requirements correctly when integrated into other applications or systems within their expected scope of use.

Q62. How can an API test be used to ensure the high-performance data store under load, preventing form-based black attacks and malicious code in mobile apps while validating requests made to URLs?

An API test can be used to measure the performance of a data store under load, including requests made by mobile apps. It can also check for malicious code in form-based black attacks and verify that URLs are valid. Automated tools such as JMeter or Gatling can be used to repeat tests multiple times, allowing an accurate evaluation of system performance when subjected to real-world use cases.

In addition to the above points being followed while preparing for an interview related to API Testing, candidates should also research further topics such as authentication techniques involving OAuth and JWT tokens; approaches like bottom-up integration or top-down integration methodologies; understanding webhooks architectures; having knowledge regarding back-end databases - MongoDB, etc., REST and SOAP protocols along with HTTP status codes.

Hope the above API testing interview questions help you to land your dream job! Stay tuned to Unstop for more useful content. 

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