REST API Error Handling u0026 Response Standards Essentials Quiz Quiz

Assess your knowledge of REST API error handling strategies, HTTP status codes, and standardized response formats. This quiz covers key principles for designing robust, user-friendly, and standards-compliant REST APIs.

1. Understanding HTTP Status Codes

   Which HTTP status code should a REST API use to indicate that a resource was not found, such as when a client requests an ID that does not exist?

   1. 404 Not Found
   2. 500 Internal Server Error
   3. 200 OK
   4. 301 Moved Permanently

   Explanation: The correct answer is 404 Not Found, which is the standard status code for a resource that could not be located. 200 OK would incorrectly suggest a successful retrieval, 500 Internal Server Error signals a server-side problem rather than absence, and 301 Moved Permanently is used for redirects, not missing resources.

2. Client Error Indication

   If a client sends a request with invalid JSON syntax, which status code is most appropriate for the REST API to return?

   1. 201 Created
   2. 403 Forbidden
   3. 204 No Content
   4. 400 Bad Request

   Explanation: 400 Bad Request is correct because it indicates that the server cannot process the request due to malformed syntax. 201 Created signifies that something was successfully created, which does not apply. 403 Forbidden means the client is not allowed to access the resource, and 204 No Content means the request succeeded but returned no content.

3. Error Object Structure

   When returning an error response, which field is typically included to help developers easily identify the issue?

   1. null value
   2. random number
   3. error message
   4. static string

   Explanation: An error message is typically provided within the error response to describe the problem in a human-readable way. A random number would have no meaning, a static string would not give context, and a null value would not deliver any useful information for debugging.

4. Response Format Best Practices

   What is the recommended content type for a REST API error response when transmitting structured data?

   1. application/word
   2. text/plain
   3. application/json
   4. image/png

   Explanation: application/json is the best practice for conveying structured data, including errors, in REST APIs for easy parsing. text/plain lacks structure and programmatic accessibility, image/png is used for images, and application/word is not a standard content type for REST API responses.

5. Handling Unauthorized Requests

   Which HTTP status code should be returned when a client provides no authentication and tries to access a protected REST API endpoint?

   1. 409 Conflict
   2. 202 Accepted
   3. 418 I'm a teapot
   4. 401 Unauthorized

   Explanation: 401 Unauthorized is used when authentication is missing or invalid for protected resources. 202 Accepted means a request was received but not yet processed, 418 I'm a teapot is a joke status and not used in practice, and 409 Conflict is used for resource state mismatches.

6. Communicating Validation Errors

   A user attempts to create a new account but submits a password that is too short. Which status code should a well-designed REST API return to indicate this validation error?

   1. 504 Gateway Timeout
   2. 422 Unprocessable Entity
   3. 206 Partial Content
   4. 301 Moved Permanently

   Explanation: 422 Unprocessable Entity is used when the request has correct syntax but contains invalid information, such as failing validation rules. 206 Partial Content is for partial data responses, 504 Gateway Timeout indicates server down issues, and 301 Moved Permanently is for URL redirection.

7. Error Details and Developer Experience

   Why should REST APIs include both a machine-readable error code and a human-readable message in error responses?

   1. To make the response larger for security
   2. To facilitate automated processing and assist developers in debugging
   3. To intentionally confuse users
   4. To comply with text encoding standards

   Explanation: Including both types of information helps machines identify the error programmatically and allows developers to quickly understand the problem. Making the response larger does not improve security, confusing users is not desirable, and text encoding standards are unrelated to this practice.

8. Correct Use of 500 Internal Server Error

   In which scenario should a REST API return the 500 Internal Server Error status code?

   1. When the user lacks permission
   2. When an unexpected server-side exception occurs
   3. When the request is successful
   4. When a resource is not found

   Explanation: 500 Internal Server Error is returned for unexpected errors on the server, such as exceptions or misconfigurations. Resource not found corresponds to 404, successful requests use 200-level codes, and permission issues typically use 403 Forbidden.

9. Consistent Error Response Patterns

   Why is it important for all error responses in a REST API to follow a consistent structure?

   1. It makes the API slower
   2. It requires less documentation
   3. It increases the server processing time
   4. It simplifies client-side error handling and improves maintainability

   Explanation: A consistent structure allows client applications to process errors reliably and reduces confusion, benefiting both development and maintenance. Less documentation is not a direct benefit, increased server time and slower APIs are negatives, not advantages.

10. Specifying Content Type in Error Responses

    If a REST API does not include a Content-Type header in its error response, what problem is most likely to occur?

    1. The error will automatically be ignored
    2. The server may become unreachable
    3. The HTTP method will change
    4. Clients may not know how to parse the response correctly

    Explanation: Without a Content-Type header, clients cannot determine the correct way to interpret the response, potentially causing parsing errors. The server remaining reachable is unrelated. Errors are not automatically ignored, and the HTTP method does not change due to missing headers.