Explore essential concepts of API error handling and HTTP response codes, enabling a clear understanding of how APIs communicate issues and successes. Ideal for developers and learners seeking to strengthen their grasp of best practices in API behaviors, error responses, and status codes.
When an API successfully processes a client request for data retrieval, which HTTP status code should it typically return?
Explanation: The 200 OK status code indicates that the API has successfully processed the request and is returning the expected data. The 400 Bad Request implies there is a client-side error, such as missing parameters. 404 Not Found is used when the requested resource does not exist. 500 Internal Server Error refers to unexpected conditions encountered on the server's side.
Which response code should an API return when it receives a malformed or invalid request from a client?
Explanation: 400 Bad Request communicates that the server cannot process the request due to a client error, such as incorrect syntax. 201 Created is used when a new resource has been successfully created. 403 Forbidden indicates the client is not allowed access, and 503 Service Unavailable means the server is temporarily unable to handle the request.
If an API is asked for a resource that does not exist, which HTTP status code is most appropriate?
Explanation: The 404 Not Found status code tells the client that the requested resource could not be located. 202 Accepted is used to indicate that the request has been received but is not yet processed. 401 Unauthorized means the user must authenticate, and 500 Internal Server Error signifies a problem on the server.
When an API requires authentication and the client does not provide valid credentials, which status code should be returned?
Explanation: A 401 Unauthorized response means the request lacks valid authentication credentials. 403 Forbidden signals that the server understands the request but refuses to authorize it. 502 Bad Gateway is a server-side error, and 204 No Content means the request succeeded but there is no content to return.
If a client tries to use an unsupported HTTP method like DELETE on a read-only resource, which status code should the API return?
Explanation: 405 Method Not Allowed is correct because it specifically indicates the method used is not allowed for the requested resource. 201 Created is about resource creation, 409 Conflict is for conflicting requests, and 301 Moved Permanently relates to resource redirection.
Which HTTP status code best indicates that an API encountered an unexpected error that prevented it from fulfilling the request?
Explanation: 500 Internal Server Error is used when the server faces an unexpected situation preventing the fulfillment of the request. 408 Request Timeout is when the server times out waiting for the client. 402 Payment Required is reserved for future use, and 202 Accepted means the request has been received and will be processed later.
When an API receives a request to create a resource that already exists, what is the standard status code to signal this conflict?
Explanation: 409 Conflict states that the request could not be completed due to a conflict with the current state of the resource, such as attempting to create a duplicate. 204 No Content shows success with no content, 307 Temporary Redirect is for URL redirections, and 400 Bad Request points to client-side errors not necessarily related to resource duplication.
If a client sends a request to add a new record and the operation is successful, which HTTP status code should the API return?
Explanation: 201 Created signals that the request has succeeded and a new resource has been created as a result. 304 Not Modified is for caching scenarios, 422 Unprocessable Entity is used for semantic errors, and 401 Unauthorized is for authentication problems.
What HTTP status code should be used when an API cannot process a request because the client took too long to send it?
Explanation: 408 Request Timeout indicates that the server did not receive a complete request from the client in the allotted time. 405 Method Not Allowed is for unsupported methods, 203 Non-Authoritative Information is rarely used and means metadata was modified, and 418 I'm a teapot is a non-standard, humorous code.
When a user is authenticated but not permitted to perform a certain action, which response code is most appropriate?
Explanation: 403 Forbidden accurately reflects that the server understands the request but refuses to authorize it, even if authentication has succeeded. 200 OK is for successful requests, 400 Bad Request means there is a problem with the client request, and 307 Temporary Redirect handles URL redirection, not authorization.