HTTP 100 Continue
The server has received the request headers and the client should proceed to send the request body.
1xx Informational
100
Continue
Description
The 100 Continue status code indicates that the initial part of a request has been received and has not yet been rejected by the server. The server intends to send a final response after the request has been fully received and acted upon. When the request contains an Expect header field that includes a 100-continue expectation, the 100 response indicates that the server wishes to receive the request payload body. The client ought to continue sending the request and discard the 100 response. If the request did not contain an Expect header field containing the 100-continue expectation, the client can simply discard this interim response.
When Is It Used?
Used when a client sends a large payload and wants to check if the server will accept it before sending the body. The client sends the headers with an Expect: 100-continue header, and the server responds with 100 Continue to indicate readiness.
Example Response
HTTP/1.1 100 ContinueRelated Status Codes
101
Switching Protocols
The server is switching protocols as requested by the client.
102
Processing
The server has received and is processing the request, but no response is available yet.
200
OK
The request has succeeded.
417
Expectation Failed
The expectation given in the Expect request header could not be met.