Explore essential concepts of API error handling and response codes in this interactive quiz. Assess your understanding of HTTP status codes, common error scenarios, and best practices for effective API communication.
When a client sends a malformed request to an API, which HTTP status code should typically be returned?
Explanation: 400 Bad Request indicates that the server could not understand the request due to invalid syntax. Returning 200 OK would incorrectly imply success. 500 Internal Server Error points to a problem on the server side, not a client issue. 301 Moved Permanently is used for URL redirection, not errors in client requests.
A user tries to access protected resources without authentication. What response code should the API return?
Explanation: 401 Unauthorized is the appropriate code when authentication is required and has not been provided or is invalid. 404 Not Found suggests the resource does not exist, which is misleading in this case. 302 Found is for temporary redirections, and 201 Created is used after a successful resource creation, both unrelated to authentication.
If a user is authenticated but not allowed to access a specific API endpoint, which status code should be returned?
Explanation: 403 Forbidden indicates that the user is authenticated but lacks the necessary permissions for the requested resource. 500 Internal Server Error is unrelated, as it refers to server issues. 200 OK signifies a successful operation, which is incorrect here. 301 Moved Permanently is about URL redirection, not access control.
When a client requests a resource that does not exist, which HTTP status code should the API use in its response?
Explanation: 404 Not Found tells the client the resource was not found on the server. 201 Created is used for successful creation events, not missing resources. 405 Method Not Allowed applies when the HTTP method is not supported, and 503 Service Unavailable means the server is temporarily unable to handle requests, which is not applicable to missing resources.
What is a common best practice when designing API error responses?
Explanation: Including both a status code and a descriptive error message helps clients quickly understand and handle errors. Returning an empty body gives no context, making debugging difficult. File download links are irrelevant in most error scenarios. Sending HTML-formatted pages is typically not helpful in API responses, which are usually in JSON or XML.
If an API user exceeds the allowed rate limit, which HTTP status code indicates this situation most appropriately?
Explanation: 429 Too Many Requests is explicitly designed to inform the client that they have sent too many requests in a given amount of time. 200 OK would incorrectly signal a successful request. 401 Unauthorized deals with authentication, and 408 Request Timeout is about connection delays, not excessive requests.
For a successful GET request that returns data, which HTTP status code should typically be used?
Explanation: 200 OK signifies the request was successful and the server responded with the requested data. 503 Service Unavailable is meant for server outages. 400 Bad Request signals a client error, and 401 Unauthorized shows missing or invalid authentication—both inappropriate for a successful GET.
If a user tries to POST to an endpoint that only supports GET, what is the correct response code?
Explanation: 405 Method Not Allowed specifically indicates that the HTTP method used is not permitted by the target resource. 200 OK and 201 Created signify successful requests, which would be incorrect here. 412 Precondition Failed relates to failed client preconditions, not HTTP methods.
Which status code should an API use if the server understands the request but cannot process the contained instructions, such as invalid input formats?
Explanation: 422 Unprocessable Entity indicates that the server understands the content type and syntax of the request but was unable to process the contained instructions. 204 No Content is for successful requests with no content in response. 302 Found is for redirection, and 500 Internal Server Error refers to generic server issues, not input processing errors.
When an unexpected condition prevents the server from fulfilling a request, which status code is standard?
Explanation: 500 Internal Server Error is used when the server encounters an unexpected issue that stops it from fulfilling the request. 301 Moved Permanently is about redirection and irrelevant to errors. 418 I'm a teapot is an unused, humorous code, and 400 Bad Request is for client mistakes, not server faults.