Client

HTTP Status Code 408 means Request Timeout. This status is returned when the server did not receive a complete request from the client within the time it was prepared to wait. It indicates that the client’s connection to the server was lost or that the server waited too long for the client to send the request. This could occur due to slow network conditions or an unresponsive client. In essence, the server is signaling that it has timed out waiting for the client to send the necessary data to complete the request.

HTTP Status Code 407 indicates Proxy Authentication Required. This status is sent when a client must authenticate itself with a proxy server before the request can proceed. It implies that the requested resource is accessible only after the client has provided valid credentials to the proxy. The server response will include a Proxy-Authenticate header field containing the authentication method required to gain access through the proxy. Essentially, it informs the client that it needs to authenticate with the proxy server to continue with the original request.

HTTP Status Code 406 signifies Not Acceptable. This status is returned when the server cannot produce a response matching the criteria specified by the Accept headers sent in the request. Essentially, the client has requested a resource in a format that the server cannot provide. For example, if a client requests a resource that can only be delivered in JSON format but specifies that it only accepts XML, the server would respond with a 406 Not Acceptable.

HTTP Status Code 405 means Method Not Allowed. This status indicates that the method specified in the request is not allowed for the resource identified by the request URL. For instance, if a client attempts to use a POST request on a resource that only supports GET requests, the server responds with a 405 Method Not Allowed. The response usually includes an Allow header that lists the valid methods for the resource, helping the client understand which actions are permissible.

HTTP Status Code 404 means Not Found. This status indicates that the server can't find the requested resource. When a client requests a URL that does not exist on the server, it returns a 404 Not Found response. This is one of the most common status codes encountered by users, often appearing when a webpage has been removed or when there’s a typo in the URL. The server recognizes the request but has no information to return, leading to this error.

HTTP Status Code 403 means Forbidden. This status indicates that the server understands the request but refuses to authorize it. This often occurs when a client attempts to access a resource without sufficient permissions or when certain restrictions, like IP blocking, are in place. Unlike 401 Unauthorized, which implies that authentication is required, 403 Forbidden indicates that even with proper authentication, access is denied.

HTTP Status Code 402 means Payment Required. This status code is currently reserved for future use and was originally intended as part of a digital cash or micropayment system. While it is defined in the HTTP specification, it is rarely used in practice. Some services may implement it for experimental payment-required functionality, but it is not widely standardized.

HTTP Status Code 401 means Unauthorized. This code indicates that the client must authenticate itself to get the requested response. Essentially, the request was received by the server, but the client failed to provide valid authentication credentials. The server response will often include a WWW-Authenticate header with information about how to authenticate.

HTTP Status Code 400 represents Bad Request. This code indicates that the server could not understand the request due to malformed syntax or an invalid request message. When a client sends a 400 error, it typically suggests an issue with the request itself, such as missing required parameters, incorrect formatting, or invalid characters. The client should review and correct the request before resubmitting.