HTTP status codes ranging from 100 to 199 are informational codes. If a browser is attempting to access a website and these codes are returned, they are normally not displayed onscreen. They are simply internal codes for the browser’s reference.
Status codes ranging from 200 to 299 are success codes. These codes are used internally by the browser as a way of confirming the success and the current status of a request. Although these codes are not normally displayed, there are troubleshooting tools that can read them, and they can be invaluable in the diagnostic process.
Status codes in the 300 to 399 range are redirection codes. They tell the Web browser that some other action must be performed in order to fulfill the request. Depending on the nature of this action, it may be performed automatically, or it may require additional user input. As an example, status code 301 indicates that a particular webpage has been permanently moved and that all future calls to the resource should be directed to a different URL.
Status codes in the 400 range are considered to be client error codes. These kinds of error codes are often security related. 400 level error codes can also be returned if the request is malformed or if the client times out.The 500 range status code are server errors, which means that server cannot process the request for an unknown reason.
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