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HTTP status codes explained for beginners

Response messages can be divided into three main types of information
-Status lines
-HTTP response headers
-HTTP response body
-HTTP response headers
-HTTP response body
The status code is in the first line of the header, in the status line.
HTTP/1.1 200 OK
Date: Sat, 22 Feb 2020 08:09:30 GMT
Content-Type: application/json; charset=utf-8
Connection: keep-alive
Server: nginx
ETag: "e287c729017cc9785487098b6b103af6"
Cache-Control: max-age=0, private, must-revalidate
X-UA-Compatible: IE=Edge,chrome=1
X-Runtime: 0.003487
The status line contains a protocol and a text phrase as well as the status code discussed here.
HTTP/1.1 200 OK
The header is further subdivided, but not in this case.

Status codes are divided into five classes
100s = information response
200s = success response
300s = Redirect
400s = Client error
500s = Server error
200s = success response
300s = Redirect
400s = Client error
500s = Server error
Below is an extract of a summary of typical status codes.
The server has not rejected the request. The client can continue the request.
The server is requesting a protocol switch.
-There is a problem with the gateway or proxy.
-The server acting as the gateway has received an invalid response.
-The server acting as the gateway has received an invalid response.
-The server is not ready to process the request.
-The server is down due to temporary heavy traffic or maintenance.
-In the case of maintenance, the Retry-After header can include an estimated restart time (in seconds).
-The server is down due to temporary heavy traffic or maintenance.
-In the case of maintenance, the Retry-After header can include an estimated restart time (in seconds).
-The server acting as the gateway did not receive a response within the specified time.
-This can be a temporary DNS anomaly due to site migration etc.
-This can be a temporary DNS anomaly due to site migration etc.
-The server does not support the version of the HTTP protocol requested.
-The current protocol is HTTP/2.
-HTTP/2 Overview | Web Fundamentals | Google Developers
-The current protocol is HTTP/2.
-HTTP/2 Overview | Web Fundamentals | Google Developers