4xxvirheistä

4xx virheistä refers to a class of HTTP status codes indicating client-side errors. These errors occur when the client (e.g., a web browser or an API consumer) makes a request that the server cannot fulfill due to an issue with the request itself. Unlike 5xx server errors, 4xx errors suggest that the problem lies with the user or application initiating the request, rather than the server's inability to process a valid request.

Common examples of 4xx errors include 400 Bad Request, which signifies that the server could not understand the request due to invalid syntax. The 401 Unauthorized error means that authentication is required and has failed or has not yet been provided. A 403 Forbidden error indicates that the server understood the request but refuses to authorize it. The widely recognized 404 Not Found error signifies that the requested resource could not be found on the server. Other less common but relevant codes include 405 Method Not Allowed, 409 Conflict, and 418 I'm a teapot. Developers often encounter and must address these errors when building web applications and APIs to ensure proper user experience and system functionality.