Status codes are numeric codes that are returned by a server in response to a client's request made to it. These codes convey the outcome of the request or provide information about the status of the server or the requested resource. In programming, status codes are commonly used in various protocols, such as HTTP, to indicate the result of a client's request to a server. Here are some common status codes used in HTTP:

1. 1xx - Informational:

These status codes indicate that the server has received the request and is processing it. They are typically used for informational purposes and do not indicate a final status.
100 Continue
101 Switching Protocols

2. 2xx - Success:

These status codes indicate that the request was successfully received, understood, and accepted by the server.
200 OK
201 Created
204 No Content

3. 3xx - Redirection:

These status codes indicate that further action needs to be taken by the client to complete the request. They are used for redirection and caching purposes.
301 Moved Permanently
302 Found (Previously "Moved Temporarily")
304 Not Modified

4. 4xx -Client Error:

These status codes indicate that the client's request contains incorrect syntax or cannot be fulfilled due to client-side errors.
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found

5. 5xx -Server Error:

These status codes indicate that the server encountered an error while processing the request. They are server-side errors.
500 Internal Server Error
501 Not Implemented
503 Service Unavailable

These status codes are standardized by organizations like the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C) to ensure interoperability and consistency across different web servers and clients. In programming, developers often check the status codes returned by HTTP requests to handle different scenarios and provide appropriate responses to users.