All 59 questions
What is the difference between PUT and PATCH, and when would you use each?
Asked in 23 of 377 interviews · last asked Oct 23 · Concept · Junior
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PUT replaces a resource’s full representation; PATCH applies changes to it. Use PUT when sending a complete replacement, and PATCH when updating only part of the resource. PUT is idempotent: repeating the same request has the same intended effect. PATCH may be idempotent, depending on the changes requested.
- PUT can also create a resource at the target URL if the API allows it.
- Do not assume PUT preserves fields left out of the request.
- PATCH behavior depends on the patch format and the API contract.
What the interviewer checks: The interviewer checks whether you understand replacement versus partial updates and how repeated requests affect the resource.
Other ways it was asked
- “What is the difference between PUT and PATCH?”
- “What is the difference between the PUT and PATCH methods?”
- “What is the difference between the HTTP POST and PUT methods?”
What HTTP methods are used in REST APIs, and when should you use each?
Asked in 20 of 377 interviews · last asked Oct 23 · Concept · Junior
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Use GET to read a resource and POST to submit data, often to create a resource. Use PUT to create or replace a resource at a known URL, and PATCH for partial updates. Use DELETE to remove a resource. HEAD returns headers without a body; OPTIONS describes communication options and supports CORS preflight.
- GET, HEAD, and OPTIONS are safe: they should not request changes to server state.
- PUT generally replaces the full resource representation; PATCH applies partial changes.
- PUT and DELETE are idempotent: repeating the request has the same intended effect, though responses may differ.
- POST and PATCH are not guaranteed to be idempotent.
What the interviewer checks: The interviewer checks whether you can choose the right method and explain its update and retry behavior.
Common mistake (in 3 of 9 reviewed answers): Many answers forget that the core set includes GET, POST, PUT, PATCH, and DELETE, so explain each one.
Other ways it was asked
- “What are the standard HTTP methods used in a REST API?”
- “Which HTTP methods are used to interact with APIs, and when would you use them?”
- “What are the common HTTP methods?”
What is the difference between GET and POST?
Asked in 9 of 377 interviews · last asked Aug 20 · Concept · Junior
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GET retrieves data from a server. POST submits data for processing, often to create a resource or trigger an action. GET is safe and idempotent: it should not request state changes, and repeating it has the same intended effect. POST is not guaranteed to be idempotent, so repeating it may create duplicates.
- HTML forms put GET data in the URL and POST data in the request body.
- GET responses can be cached; POST responses are cacheable only under specific conditions.
- POST is not automatically secure because it uses a body; both methods need HTTPS to protect data.
What the interviewer checks: The interviewer checks whether you understand each method’s purpose, safety, and behavior when requests are repeated.
Other ways it was asked
- “What is the difference between the GET and POST methods in an API?”
- “What is the difference between the GET and POST methods in an HTML form?”
- “What is the difference between GET and POST methods in PHP?”
What do HTTP 401 and 403 mean, and how do you troubleshoot each?
Asked in 5 of 377 interviews · last asked Oct 13 · Concept · Junior
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HTTP 401 means the request lacks valid authentication credentials. HTTP 403 means the server understood the request but refuses access, often because permissions are missing. For 401, check the Authorization header, token validity, and authentication scheme. For 403, check roles, scopes, resource permissions, and access policies.
- A 401 response must include a WWW-Authenticate header describing an authentication challenge.
- For 401, check whether credentials are missing, expired, revoked, or invalid.
- A 403 does not always mean the user is authenticated; other access policies can block requests.
- Retrying a 403 with the same credentials usually will not help.
What the interviewer checks: The interviewer checks whether you distinguish authentication from access restrictions and can troubleshoot both.
Other ways it was asked
- “What do HTTP status codes 401 and 403 mean, and when would you use each?”
- “What is the difference between HTTP status codes 401 and 403?”
- “What HTTP status codes indicate authentication and authorization failures?”
What are the different types of API calls?
Asked in 3 of 377 interviews · last asked Oct 3 · Concept · Junior
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REST API calls are usually grouped by HTTP method. GET reads data, POST submits data or creates a resource, PUT replaces or creates a resource at a known URL, PATCH partially updates a resource, and DELETE removes it. HEAD returns headers without a response body; OPTIONS reports supported communication options.
- GET and HEAD should not request changes to server data.
- PUT and DELETE are idempotent: repeating the same request has the same intended effect.
- POST and PATCH are not guaranteed to be idempotent.
What the interviewer checks: The interviewer checks whether you can choose the right HTTP method and understand its expected behavior.
Other ways it was asked
- “What are the different types of APIs?”
- “What types of API requests are there?”
When you design a REST API endpoint to create a resource, what HTTP status code do you typically return, and what do you include in the response body and headers?
Asked in 2 of 377 interviews · last asked Jul 16 · Concept · Junior
Other ways it was asked
- “When designing a RESTful API endpoint in PHP to create a resource, which HTTP method and typical success status code do you use, and what should the response include?”
Which HTTP error status codes do you commonly use in APIs, and in what scenarios?
Asked once · last asked Feb 10 · Concept · Mid-level
When would you choose for a web API endpoint to return a 200, 204, 400, 404, or 409 status code, and what practical client behaviors are you optimizing for with each choice?
Asked once · last asked Feb 16 · Concept · Mid-level
When might a web API return a 409 Conflict response, and how should a client handle it?
Asked once · last asked Feb 16 · Scenario · Mid-level
A user wants to update only their profile bio, leaving their email and name unchanged. Would you use PUT or PATCH, and what could happen if you used the wrong method?
Asked once · last asked Mar 10 · Scenario · Junior
When designing a REST endpoint in PHP to update a resource, how do you decide between PUT and PATCH, and what should each mean semantically?
Asked once · last asked Mar 26 · Concept · Mid-level
When would you return 202 Accepted instead of 201 Created for a create operation, and how would you communicate completion to the client?
Asked once · last asked Mar 26 · Concept · Mid-level
Name six commonly used HTTP status codes and explain what each one indicates.
Asked once · last asked Apr 17 · Concept · Junior
What information should a REST API request include when connecting ServiceNow to Okta?
Asked once · last asked Apr 21 · Tooling · Mid-level
Why is data sent in the request body with POST rather than in the URL?
Asked once · last asked May 19 · Concept · Junior
If I want to send parameters in the URL with a POST request, how can I do that?
Asked once · last asked May 19 · Concept · Junior
If a 17-year-old submits a structurally valid request that violates an age eligibility rule, what error code should the API return?
Asked once · last asked Jul 17 · Scenario · Mid-level
What do HTTP status codes 200 and 400 indicate in a banking API, and how should they be interpreted?
Asked once · last asked Jul 17 · Concept · Mid-level
How do you pass a user's query in an API request?
Asked once · last asked Jul 31 · Scenario · Mid-level
When building a RESTful service in ASP.NET Core, how do you ensure controller actions return appropriate HTTP status codes, and what helpers does the framework provide to make this easier?
Asked once · last asked Aug 5 · Tooling · Mid-level
When designing a REST API, how do you choose the right HTTP method and status codes for creating a resource?
Asked once · last asked Aug 14 · Concept · Mid-level
How do you return an HTTP status code along with data from a Web API action? What helper methods does the controller base class provide for this?
Asked once · last asked Aug 15 · Tooling · Junior
What is the difference between GET_ENTITY and GET_ENTITYSET?
Asked once · last asked Aug 25 · Concept · Mid-level
What should an API do when a PATCH request targets a record that has been deleted?
Asked once · last asked Aug 31 · Scenario · Mid-level
How would you evaluate whether the HTTP response codes chosen for an API endpoint are appropriate?
Asked once · last asked Sep 4 · Concept · Mid-level
Other ways it was asked
- “What do you think of the HTTP response codes defined for an API endpoint?”
If an API queues a request for processing, how should the user receive the response?
Asked once · last asked Sep 10 · Design · Senior
What is the difference between the HTTP 409 Conflict and 412 Precondition Failed status codes?
Asked once · last asked Sep 23 · Concept · Mid-level
Which HTTP actions must a Django REST Framework view support to provide full CRUD functionality?
Asked once · last asked Sep 29 · Concept · Mid-level
What is the purpose of HTTP response codes, such as 201, 404, and 500?
Asked once · last asked Oct 13 · Concept · Junior
What is the difference between the PUT and POST methods in Spring Boot?
Asked once · last asked Oct 13 · Concept · Junior
What are the HTTP status codes 200, 201, 400, 401, 404, and 500?
Asked once · last asked Oct 21 · Concept · Junior
What is the difference between @QueryParam and @PathParam?
Asked once · last asked Oct 22 · Concept · Junior
Can a new record be created using GET, or should POST be used?
Asked once · last asked Jan 24 · Concept · Junior
How would you choose an HTTP method for a request from an Angular service?
Asked once · last asked Sep 29 · Concept · Junior
Other ways it was asked
- “Which HTTP method would you use for the request from an Angular service?”
- “Which HTTP method would you use for the request from an Angular service, and why?”
What information should a client provide in an object-storage PUT request, such as the bucket name, object key, and payload?
Asked once · last asked Apr 22 · Design · Mid-level
Can you partially update data using the PUT method?
Asked once · last asked Apr 30 · Concept · Junior
Can GET be used to send data?
Asked once · last asked May 9 · Concept · Junior
How exactly does a POST request work?
Asked once · last asked May 19 · Concept · Junior
What does the HTTP 409 status code mean?
Asked once · last asked Jun 4 · Concept · Junior
What do you understand by payload in RESTful web services?
Asked once · last asked Jul 16 · Concept · Junior
What does the 400 Bad Request status code mean?
Asked once · last asked Jul 17 · Concept · Junior
What do you understand when you see a 403 Forbidden status code?
Asked once · last asked Jul 17 · Concept · Junior
What does the 422 Unprocessable Entity status code mean?
Asked once · last asked Jul 17 · Concept · Junior
What does the 429 Too Many Requests status code mean?
Asked once · last asked Jul 17 · Concept · Junior
What does the 500 Internal Server Error status code mean?
Asked once · last asked Jul 17 · Concept · Junior
What does the 503 Service Unavailable status code mean?
Asked once · last asked Jul 17 · Concept · Junior
Which HTTP method would you use to insert data into a database through an API?
Asked once · last asked Jul 22 · Concept · Junior
When retrieving an authentication token, should you use POST or GET?
Asked once · last asked Aug 11 · Concept · Junior
What is the purpose of HTTP status codes in REST APIs?
Asked once · last asked Aug 20 · Concept · Junior
In a REST API request, which parts are important to configure?
Asked once · last asked Sep 2 · Concept · Junior
How can you tell from an API response whether it was successful?
Asked once · last asked Sep 2 · Concept · Junior
Why should an API return an error status code instead of returning 200 for a failed request?
Asked once · last asked Sep 15 · Concept · Junior
What is the HTTP status code for a bad request, and when do we get it?
Asked once · last asked Sep 16 · Concept · Junior
What HTTP status code should an API return for an unhandled error or internal server error?
Asked once · last asked Sep 16 · Concept · Junior
What does HTTP status code 204 mean?
Asked once · last asked Sep 21 · Concept · Junior
When do you return a 502 HTTP status code?
Asked once · last asked Oct 1 · Concept · Mid-level
What are the standard HTTP status codes, and what do they mean?
Asked once · last asked Oct 5 · Concept · Junior
If an unhandled NullReferenceException occurs in an API, what HTTP status code is typically returned?
Asked once · last asked Oct 16 · Concept · Mid-level
Other ways it was asked
- “If an API encounters a NullReferenceException, what status code will it return?”
What is the meaning of content negotiation in Web API?
Asked once · last asked Oct 16 · Concept · Junior
More REST API interview questions
- All REST API interview questions
- REST API Basics Interview Questions
- REST API Design and Versioning Interview Questions
- REST API Implementation Interview Questions
- API Validation, Error Handling, and Testing Interview Questions
- REST API Security and Authentication Interview Questions
- API Pagination, Performance, and Rate Limiting Interview Questions
- API Idempotency, Retries, and Consistency Interview Questions
- API Integration and Webhooks Interview Questions
How this list is made
Every question here was asked by a real interviewer in a real job interview that a candidate ran MeetAssist in. After the call, the interviewer's questions are pulled from the transcript. Practice sessions, tests, exams and anything that was not a job interview are dropped.
Questions are rewritten so they make sense on their own: names of people, employers and clients are removed, and speech-to-text mistakes are fixed. Small talk, logistics and questions about one candidate's own résumé are left out. Rephrasings of the same question are merged, and the count is the number of different interviews it came up in.
The interviews come from candidates who use MeetAssist, so they lean towards software, data and AI roles: the shares describe these interviews, not every REST API interview. Answers to the most asked questions are written and checked by an editor; a "common mistake" is shown only when reviews of real answers in these interviews show it, with the count.
377 interviews, 243 candidates, Jan 2026 to Oct 2026. Updated every month with new interviews.
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