The 200 series is used for indicating the success of the operation requested by the client. This tells the client that the request has been processed successfully, the necessary changes have been made to the resource, and a successful response has been issued to the client:

• 200 OK: This status code indicates that the request processing is successful and the server responds with the success response body.
• 201 Created: This status code indicates that the server processed the request successfully and a new resource is created on the server.

• 202 Accepted: This status is used to indicate that the server has accepted the request. Generally this status code is used when the server takes longer time to process the request. When the server accepts the request, it sends the 202 status code to the client indicating that it has accepted the request and takes time to complete the processing of the request.

• 203  Non-Authoritative Information: This status code used to indicate that the server(origin) has processed the request successfully but the enclosed response is modified from that of origin server's original response. Sometimes the HTTP proxy which is in between the client and the server can modify the response coming from the server.
  The HTTP proxy changes the status code to 203 if it modifies the response. 203 status code is a Non-Authoritative Information and indicates the transformation applied on the original response from the server. It changes the original HTTP status code and there is no way to check what was the original status code from the server.
  As an alternative to 203 HTTP status code, RFC suggest to use a warning header set to 214 Transformation applied. In case of this warning header, the original status code from the origin will not be modified once the proxy applies any transformation on the response.
• 204 No Content: This status code indicates that the request processing is successful and the server responds with an empty response body. Usually, the 204 No Content status code is used for a successful delete operation on a resource.