What are HTTP Status Codes?

Once a while when you are surfing Internet you might have come across a sudden ‘404 – Not found’ status code. It may have crossed your mind why ‘404 not 804’. In today’s post, I will try to explain all you need to know as a non-techie about HTTP status codes.

An HTTP status code is a numeric code that is returned by a web server in response to a client’s request made over HTTP (Hypertext Transfer Protocol). It indicates the outcome of the server’s attempt to fulfill the client’s request. HTTP status codes are categorized into different classes, each representing a specific type of response.

Five classes of HTTP status codes

1xx Informational: Indicates that the server has received the request and is continuing the process.
2xx Success: Indicates that the request was successfully received, understood, and accepted.
3xx Redirection: Indicates further action needs to be taken by the client to complete the request.
4xx Client Errors: Indicates that the client has sent a malformed request or the server cannot process it.
5xx Server Errors: Indicates that the server failed to fulfil a valid request due to an error on the server side.

HTTP status code 1xx Response

100 Continue: The server has received the initial part of the request and the client should proceed with the remainder of the request.
101 Switching Protocols: The server is willing to change the application protocol being used on this connection.

HTTP status code 2xx Success

200 OK: The request has succeeded.
201 Created: The request has been fulfilled and a new resource has been created.
202 Accepted: The request has been accepted but may not be processed yet.
204 No Content: The server successfully processed the request but is not returning any content.

HTTP status code 3xx Redirection

301 Moved Permanently: The requested resource has been permanently moved to a new location.
302 Found: The requested resource resides temporarily under a different URL.
304 Not Modified: The resource has not been modified since the last request.

HTTP status code 4xx Client Error

400 Bad Request: The server cannot process the request due to client error.
401 Unauthorized: Authentication is required to access the resource.
403 Forbidden: The server understood the request but refuses to authorize it.
404 Not Found: The requested resource could not be found on the server.
405 Method Not Allowed: The request method is not supported for the requested resource.
406 Not Acceptable: The server cannot produce a response matching the accept headers of the request.
408 Request Timeout: The server timed out waiting for the request.
409 Conflict: The request could not be completed due to a conflict with the current state of the resource.

HTTP status code 5xx Client Error

500 Internal Server Error: A generic error message returned when the server encounters an unexpected condition.
501 Not Implemented: The server does not support the functionality required to fulfill the request.
502 Bad Gateway: The server received an invalid response from an upstream server.
503 Service Unavailable: The server is currently unable to handle the request due to temporary overloading or maintenance.
504 Gateway Timeout: The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server.
505 HTTP Version Not Supported: The server does not support the HTTP protocol version used in the request.

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